Electrode sheet, electrode assembly and battery cell

Abstract

The present application relates to the technical field of batteries. Provided are an electrode sheet, an electrode assembly and a battery cell. The electrode sheet comprises a current collector, an active material layer and a tab. The current collector comprises a main body and a protruding portion protruding outward from an edge portion of the main body. The active material layer is arranged on the main body and the protruding portion, and the tab is connected to the main body.

Description

Electrode sheets, electrode assemblies and battery cells

[0001] This application claims priority to Chinese Patent Application No. 202423136576.9, filed on December 18, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to an electrode sheet, electrode assembly, and battery cell. Background Technology

[0003] A battery cell includes a housing and an electrode assembly disposed within the housing. Electrode assemblies can be classified into laminated electrode assemblies and wound electrode assemblies based on their forming method. Laminated electrode assemblies include multiple separators, negative electrode plates, separators, and positive electrode plates stacked sequentially. Invention Overview

[0004] Current stacked electrode assemblies have relatively low energy density.

[0005] Embodiments of this application provide an electrode sheet, an electrode assembly, and a battery cell, which can improve the energy density of a stacked electrode assembly.

[0006] In a first aspect, this application provides an electrode sheet, which includes a current collector, an active material layer, and a tab; the current collector includes a main body and a protrusion extending outward from the edge of the main body; the active material layer is disposed on the main body and the protrusion; and the tab is connected to the main body.

[0007] Secondly, this application provides an electrode assembly, which includes a plurality of negative electrode plates, a plurality of positive electrode plates, and a plurality of separators; the plurality of positive electrode plates and the plurality of negative electrode plates are arranged alternately and stacked in sequence; the plurality of separators are used to insulate and isolate two adjacent positive electrode plates and negative electrode plates; wherein, the negative electrode plate is the aforementioned electrode plate.

[0008] Thirdly, this application provides a battery cell, which includes a housing and the aforementioned electrode assembly; the electrode assembly is disposed inside the housing; wherein a positive electrode or a negative electrode is connected to the housing. Beneficial effects

[0009] In this application, by providing protrusions at the edges of the main body, the amount of active material layer on the electrode can be increased, thereby improving the energy density of the electrode assembly and thus the energy density of the battery cell. Attached Figure Description

[0010] Figure 1 is a schematic diagram of the structure of the electrode provided in an embodiment of this application;

[0011] Figure 2 is a side view of the electrode provided in an embodiment of this application;

[0012] Figure 3 is a schematic diagram of the current collector structure provided in an embodiment of this application.

[0013] Figure 4 is a partial structural schematic diagram of the current collector provided in an embodiment of this application;

[0014] Figure 5 is a schematic diagram of the structure of another electrode provided in an embodiment of this application;

[0015] Figure 6 is a schematic diagram of the structure of the electrode assembly provided in an embodiment of this application;

[0016] Figure 7 is a side view of the electrode assembly provided in an embodiment of this application;

[0017] Figure 8 is an enlarged view of point A in Figure 6;

[0018] Figure 9 is a schematic diagram of the structure of the battery cell provided in an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures:

[0020] 1-Electrode; 11-Current collector; 111-Main body; 112-Protrusion; 113-First edge Z; 114-Second edge Z; 115-Third edge Z; 116-First edge B;

[0021] 12-Active material layer; 13-Electrode; 131-Extended edge; 14-First corner;

[0022] 2-Electrode assembly; 21-Negative electrode; 22-Positive electrode; 221-Positive tab; 23-Separator;

[0023] 3-Battery cell; 31-Casing; 32-Positive terminal. Embodiments of the present invention

[0024] Before introducing the electrode sheet, electrode assembly, and battery cell provided in this application, the relevant technologies of this application will be explained first.

[0025] In related technologies, a battery cell includes a casing and electrode assemblies disposed within the casing. Electrode assemblies can be categorized into stacked electrode assemblies and wound electrode assemblies based on their forming method. Stacked electrode assemblies include multiple sequentially stacked separators, negative electrode sheets, separators, and positive electrode sheets. During the production of stacked electrode assemblies, to improve cell reliability, an insulating layer needs to be placed at the edge of the positive electrode sheet to prevent lithium deposition at the edge. Based on existing insulating layer placement processes, the minimum width of the insulating layer that can be placed at the edge of the positive electrode sheet is 2mm, and the minimum thickness is 20μm. The thickness of a typical positive electrode sheet is 100~160μm. In the thickness direction of the positive electrode sheet, the insulating layer occupies 12.5%~20% of the positive electrode sheet's thickness. This results in a capacity loss of 1%~2% for the battery cell.

[0026] In consumer electronics products such as smartwatches and AR glasses, the battery cells used are not only small in size, but also vary significantly in length and width. Correspondingly, the electrode plates that make up these cells are also small in size, and their length and width also vary significantly. Using an insulating layer to address the lithium plating problem at the edges of the positive electrode would result in a significant capacity loss for these types of cells.

[0027] Based on this, in order to improve the energy density of battery cells, especially the energy density of small-sized battery cells, embodiments of this application provide an electrode sheet, an electrode assembly, and a battery cell. These will be described in detail below through the embodiments.

[0028] Please refer to Figures 1 to 3. Figure 1 is a structural schematic diagram of the electrode 1 provided in an embodiment of this application, Figure 2 is a side view of the electrode 1 provided in an embodiment of this application, and Figure 3 is a structural schematic diagram of the current collector 11 provided in an embodiment of this application. An embodiment of this application provides an electrode 1. The electrode 1 includes a current collector 11, an active material layer 12, and tabs 13. The current collector 11 includes a main body 111 and a protrusion 112 extending outward from the edge of the main body 111. The active material layer 12 is disposed on the main body 111 and the protrusion 112. The tabs 13 are connected to the main body 111.

[0029] It is understandable that the protrusion 112 makes the structure of the electrode 1 after removing the tab 13 irregular. For example, when the main body 111 is rectangular, part of the edge of the main body 111 is connected to the tab 13, and part of the edge of the main body 111 is connected to the protrusion 112.

[0030] It is understood that the tab 13 and the current collector 11 can be integrally formed. For example, a portion of a foil can be used to set the active material layer 12, while another portion can be left empty to serve as the tab 13. The tab 13 can also be soldered to the current collector 11.

[0031] It is understood that the main materials of the active material layer 12 of the positive electrode 22 include, but are not limited to, lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium iron phosphate, conductive agent, and binder. The main materials of the active material layer 12 of the negative electrode 21 include, but are not limited to, graphite, conductive agent, and binder.

[0032] In addition, to avoid lithium plating, the electrode 1 provided in this embodiment can be a negative electrode 21, thereby providing more lithium intercalation sites for the cell 3, so as to effectively prevent lithium ions from being deposited in the form of metallic lithium.

[0033] It is understandable that this is done in order to control the space occupied by the protrusion 112. In the stacked electrode assembly 2 in which the electrode 1 is applied, the protrusion 112 is configured to be opposite to the tab of the positive electrode along the thickness direction of the electrode 1. That is, the protrusion 112 of the electrode 1 provided in this embodiment can be opposite to the tab of the positive electrode. In this way, the space occupied by the protrusion 112 is the space between the tabs of the positive electrode, so as not to affect the external dimensions of the cell 3.

[0034] In this embodiment, by providing a protrusion 112 at the edge of the main body 111, the amount of active material layer 12 of the electrode 1 can be increased, thereby improving the energy density of the electrode assembly 2 and thus improving the energy density of the battery cell 3.

[0035] Furthermore, when the electrode 1 provided in this embodiment is a negative electrode 21, by providing a protrusion 112 on the edge of the main body 111, the amount of lithium intercalation sites in the electrode assembly 2 can be increased, thereby effectively preventing lithium ions from being deposited and precipitated in the form of metallic lithium, thus reducing the risk of lithium plating in the electrode assembly 2. In this way, the reliability of the cell 3 can be improved.

[0036] Please refer to Figure 4, which is a partial structural schematic diagram of the current collector 11 provided in an embodiment of this application. In one embodiment, the main body 111 has a first edge Z113 and a second edge Z114 connected to each other. The first edge Z113 and the second edge Z114 are set at an angle. A protrusion 112 protrudes outward from a portion of the first edge Z113, and the protrusion 112 has two first edges B116 extending along the protrusion direction. One of the first edges B116 is collinear with the second edge Z114.

[0037] It is understandable that collinear setting means that in a plane parallel to electrode 1, the projection of the first edge B116 and the projection of the second edge Z114 are on the same straight line.

[0038] It is understandable that in order to reduce stress concentration at the corners of the electrode 1 and prevent the sharp corners of the electrode 1 from piercing the diaphragm 23, it is necessary to round off the corners of the electrode 1. However, rounding off the corners on the main body 111 will result in the loss of a portion of the current collector 11 on the main body 111 that can be used to set the active material layer 12.

[0039] Based on this, in this embodiment, by arranging a first edge B116 and a second edge Z114 collinearly, the number of corners in the main body 111 can be reduced. This increases, on the one hand, the area of ​​the active material layer 12 that can be disposed on the electrode 1, thereby increasing the amount of active material layer 12 disposed on the electrode 1, which helps to improve the energy density of the electrode assembly 2; on the other hand, it reduces the corner treatment of the electrode 1, thereby reducing areas of stress concentration on the electrode 1, and thus improving the stress state of the electrode 1.

[0040] Referring to Figure 4, in one embodiment, an obtuse angle α is formed between the first edge B116, which is away from the second edge Z114, and the first edge Z113. This reduces stress concentration at the corner formed between the first edge B116 and the first edge Z113, thereby improving the stress state at the connection between the first edge B116 and the first edge Z113.

[0041] It is understood that the obtuse angle α is located outside the protrusion 112.

[0042] Please refer to Figure 4. In one embodiment, 90° < α ≤ 135°.

[0043] It is understood that the obtuse angle α includes, but is not limited to, 91°, 92°, 93°, 94°, 95°, 96°, 97°, 98°, 99°, 100°, 101°, 102°, 103°, 104°, 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119°, 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, and 135°.

[0044] In this embodiment, the above-mentioned arrangement satisfies the requirement that an obtuse angle α be formed between the first edge B116 and the first edge Z113, and also allows the protrusion 112 to have a larger area, thereby allowing for the provision of more active material layers 12 to improve the energy density of the electrode assembly 2.

[0045] Please refer to Figure 4. In one embodiment, the distance between the side of the protrusion 112 away from the body 111 and the edge of the body 111 connected thereto is H, which satisfies: 0 < H ≤ 2 mm.

[0046] It is understood that the distance H between the side of the protrusion 112 away from the main body 111 and the edge of the main body 111 connected thereto is, but is not limited to, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, and 2mm.

[0047] It is understandable that a separator 23 is used to insulate and isolate adjacent positive electrode plates 22 and negative electrode plates 21. In order to improve the reliability of the separator 23 in insulating and isolating the positive electrode plates 22 and negative electrode plates 21, the separator 23 is set beyond the edge of the main body 111, generally by 2 mm.

[0048] Based on this, in this embodiment, the above-mentioned arrangement can not only form the protrusion 112 to improve the energy density of the electrode assembly 2, but also effectively ensure the insulation between the electrode 1 and the adjacent electrode 1 of the other polarity, thereby improving the reliability of the electrode assembly 2.

[0049] It is understandable that if the diaphragm 23 extends 1 mm beyond the edge of the main body 111, then the maximum distance H between the side of the protrusion 112 away from the main body 111 and the edge of the main body 111 connected to it is 1 mm.

[0050] Referring to Figure 1, in one embodiment, the body 111 has a third edge Z115, a first edge Z113, and a second edge Z114 connected sequentially. Both the third edge Z115 and the second edge Z114 are angled to the first edge Z113. A tab 13 is connected to the first edge Z113. The distance between the tab 13 and the third edge Z115 is not equal to the distance between the tab 13 and the second edge Z114. This allows the assembler to determine whether the tab 13 of the electrode 1 should be located on the left or right side of the body 111 based on these two unequal distances, thereby improving the speed of assembling it with an electrode 1 of the other polarity.

[0051] Please refer to Figure 1. In one embodiment, the minimum distance between the tab 13 and the third edge Z115 is dmin1, 0≤dmin1≤20mm, or the minimum distance between the tab 13 and the second edge Z114 is dmin2, 0≤dmin2≤20mm.

[0052] The minimum spacing dmin1 between the tab 13 and the third edge Z115 includes, but is not limited to, 0, 0.1 mm, 1.2 mm, 2.3 mm, 3.4 mm, 4.5 mm, 5.6 mm, 6.7 mm, 7.8 mm, 8.9 mm, 10.0 mm, 11.1 mm, 12.2 mm, 13.3 mm, 14.4 mm, 15.5 mm, 16.6 mm, 17.7 mm, 18.8 mm, and 20 mm.

[0053] The minimum spacing dmin2 between the tab 13 and the second edge Z114 includes, but is not limited to, 0, 0.5 mm, 2.5 mm, 3.6 mm, 4.7 mm, 5.8 mm, 6.9 mm, 8.0 mm, 9.1 mm, 10.2 mm, 11.5 mm, 12.6 mm, 13.7 mm, 14.8 mm, 15.9 mm, 16.0 mm, 17.1 mm, 18.2 mm, 19.3 mm, and 20 mm.

[0054] In this embodiment, the above-mentioned limitation facilitates the offset of the tab 13 to one side of the main body 111, thereby enabling the assembly personnel to determine whether the tab 13 of the electrode 1 should be located on the left or right side of the main body 111 based on the distance of the tab 13 from the side of the main body 111, thereby improving the speed of assembling it with the electrode 1 of the other polarity.

[0055] Referring to Figure 1, in one embodiment, the distance between the tab 13 and the third edge Z115 is d1. The distance between the tab 13 and the second edge Z114 is d2, satisfying: |d1-d2|≥2mm.

[0056] It is understood that the absolute values ​​of the interpolation between spacing d1 and spacing d2 include, but are not limited to, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, and 3mm.

[0057] It is understandable that when the tab 13 and the protrusion 112 are located on the same side of the main body 111, the location of the tab 13 does not affect the location of the protrusion 112.

[0058] In this embodiment, the above-mentioned limitations make it easier for assembly members to directly observe the tab 13 with the naked eye, and clearly distinguish whether the tab 13 is located on the left or right side of the electrode 1, thereby improving the speed of assembling the electrode 1 with the electrode 1 of the other polarity.

[0059] Please refer to Figure 5, which is a schematic diagram of the structure of another electrode 1 provided in an embodiment of this application. In one embodiment, the body 111 has a first edge Z113 and a third edge Z115 connected to each other. The first edge Z113 and the third edge Z115 are set at an angle. One side of the electrode tab 13 is connected to the first edge Z113. Along the extending direction of the electrode tab 13, the electrode tab 13 has two extending edges 131, one of which is collinear with the third edge Z115.

[0060] It is understandable that in order to reduce stress concentration at the corners of the electrode 1 and prevent the sharp corners of the electrode 1 from piercing the diaphragm 23, it is necessary to round off the corners of the electrode 1. However, rounding off the corners on the main body 111 will result in the loss of a portion of the current collector 11 on the main body 111 that can be used to set the active material layer 12.

[0061] Based on this, in this embodiment, by arranging an extended edge 131 collinearly with the third edge Z115, the number of corners in the main body 111 can be reduced. This increases, on the one hand, the area of ​​the active material layer 12 that can be disposed on the electrode 1, thereby increasing the amount of active material layer 12 disposed on the electrode 1, which helps to improve the energy density of the electrode assembly 2; on the other hand, it reduces the corner treatment of the electrode 1, thereby reducing areas of stress concentration on the electrode 1, and thus improving the stress state of the electrode 1.

[0062] In addition, by setting an extended edge 131 collinear with the third edge Z115, the problems of burrs and cracks in the electrode 1 caused by the need for rounding the corners on the side of the variable body 111 near the tab 13 are avoided.

[0063] Referring to Figure 1 or Figure 5, in one embodiment, the connection between the electrode tab 13 and the current collector 11 has a first corner 14. A rounded corner R1 is provided at the first corner 14. Rounded corners R2 are provided at the other corners of the electrode 1, and the radius of the rounded corner R1 is larger than the radius of the rounded corner R2.

[0064] For example, the radius of the fillet R2 is 0.3mm, while the radius of the fillet R1 can be 2mm.

[0065] Among them, the radius of at least one of the rounded corners R1 and R2 is gradually changing. By setting the corners on the electrode 1 to be gradually changing, it can prevent sharp structures from appearing at each corner of the electrode 1 to avoid scratching the diaphragm, and can also guide the electrode assembly 2 assembled from the electrode 1 when it is installed into the outer shell 31 of the cell 3, so as to improve the smoothness of assembly.

[0066] Specifically, when the radius of the fillet R1 is gradually changing, it can be that the radius of the fillet R1 gradually increases from the edge of the tab 13 to the edge of the body 111, or it can be that the radius of the fillet R1 gradually decreases from the edge of the tab 13 to the edge of the body 111, or it can be that the radius of the fillet R1 gradually decreases from a certain position of the fillet R1 to the edge of the tab 13 and the edge of the body 111 respectively.

[0067] Specifically, the radius of the rounded corner R2 is gradually changing. It can be that the radius of the rounded corner R2 gradually increases or decreases from one edge of the main body 111 to the other edge of the main body, or it can be that the radius of the rounded corner R2 gradually decreases from a certain position of the rounded corner R2 to the two edges of the main body 111.

[0068] In this embodiment, the dimensions of the connection between the tab 13 and the main body 111 can be increased by the above-described configuration. This not only increases the area of ​​the tab 13, thereby increasing the strength of the connection between the tab 13 and the main body 111 and preventing the connection between the tab 13 and the main body 111 from breaking due to welding, but also improves the ease of welding the tab 13. Furthermore, it increases the current-carrying area between the tab 13 and the main body 111, thereby reducing the internal resistance of the cell 3.

[0069] Referring to Figure 1 or Figure 5, in one embodiment, the tab 13 and the protrusion 112 are located on the same side of the body 111. This allows the protrusion 112 and the tab 13 to share a portion of their height space, thereby reducing the space occupied by the protrusion 112 and improving the structural compactness of the electrode assembly 2.

[0070] Please refer to Figures 6 and 7. Figure 6 is a schematic diagram of the electrode assembly 2 provided in an embodiment of this application, and Figure 7 is a side view of the electrode assembly 2 provided in an embodiment of this application. An embodiment of this application provides an electrode assembly 2. The electrode assembly 2 includes multiple negative electrode plates 21, multiple positive electrode plates 22, and multiple separators 23. The multiple positive electrode plates 22 and multiple negative electrode plates 21 are alternately arranged and stacked. The multiple separators 23 are used to insulate and isolate adjacent positive electrode plates 22 and negative electrode plates 21. The negative electrode plate 21 is the electrode plate 1 provided in some embodiments of this application.

[0071] It is understandable that the protrusion 112 is positioned adjacent to the portion of the positive electrode 22 where lithium deposition is likely to occur.

[0072] In the embodiments, by using the electrode 1 provided in some embodiments of this application as the negative electrode 21, the energy density of the electrode assembly 2 can be improved, thereby improving the energy density of the battery cell 3.

[0073] In one embodiment, the positive electrode 22 has a positive tab 221. Along the stacking direction, the positive tab 221 is disposed opposite to the protrusion 112. This allows the active material layer 12 of the protrusion 112 of the negative electrode 21 to be opposite to the active material layer 12 on the positive tab 221 of the positive electrode 22. This effectively prevents lithium ions at the edge of the positive electrode 22 from depositing as metallic lithium, thereby reducing the risk of lithium plating in the electrode assembly 2, while simultaneously increasing the energy density of the electrode assembly 2. This improves the reliability of the battery cell 3.

[0074] Furthermore, during the coating process of the positive electrode active material layer 12, the coating position is unlikely to be misaligned in any of the four directions (front, back, left, right) relative to the current collector 11 of the positive electrode sheet 22. Such misalignment would result in residual positive electrode active material on the electrode tab 13 formed by die-cutting the positive electrode sheet 22 after coating. Therefore, in this embodiment, by aligning the positive electrode tab 221 with the protrusion 112, the risk of lithium plating due to residual positive electrode active material on the positive electrode tab 221 can be reduced.

[0075] Please refer to Figure 8, which is an enlarged view of point A in Figure 6. In one embodiment, the positive electrode tab 221 has a width dimension W1. In the direction of the width dimension W1 of the positive electrode tab 221, the protrusion 112 has a dimension W2, satisfying: W2 > W1. In this way, the overlap between the protrusion 112 and the positive electrode tab 221 is increased, thereby effectively preventing lithium ions from depositing as metallic lithium at the edge of the positive electrode 22.

[0076] Wherein, dimension W2 is the dimension of the side of the protrusion 112 away from the main body 111.

[0077] In one embodiment, along the stacking direction, the thickness of the positive electrode 22 located at the first and last positions is D1, and the thickness of the remaining positive electrode 22 is D2, satisfying: D1 > D2.

[0078] It is understandable that after the positive electrode 22, the separator 23, and the negative electrode 21 are stacked in sequence, ultrasonic waves are used to weld the tabs 13 of the positive electrode 22 into one piece. Since ultrasonic welding uses high-frequency vibration energy to make the surfaces of the materials to be welded rub against each other, thereby generating heat, and achieving the connection of materials under pressure.

[0079] Therefore, when the positive electrode tabs 221 are welded together, vibrations acting on the positive electrode sheet 22 can easily cause damage or even breakage to the positive electrode sheets 22 located at the beginning and end of the stacking direction. Based on this, in this embodiment, the thickness D1 of the positive electrode sheets 22 located at the beginning and end is set to be larger, thereby improving the strength of the positive electrode sheets 22 located at the beginning and end, so as to avoid damage to them during the welding process.

[0080] In one embodiment, 16μm≤D1≤25μm, 6μm≤D2≤12μm. This ensures that the positive electrode 22 located at the beginning and end positions, as well as other positive electrode 22 located between the beginning and end positions, all have suitable thickness dimensions, so as to ensure smooth welding while controlling the material cost of the positive electrode 22.

[0081] The thickness D1 includes, but is not limited to, 16μm, 16.5μm, 17μm, 17.5μm, 18μm, 18.5μm, 19μm, 19.5μm, 20μm, 20.5μm, 21μm, 22μm, 23μm, 24μm, and 25μm.

[0082] Thickness D2 includes, but is not limited to, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, and 12μm.

[0083] In one embodiment, along the stacking direction, the thickness of the negative electrode 21 located at the first and last positions is D3, and the thickness of the remaining negative electrode 21 is D4, satisfying: D3 > D4.

[0084] It is understandable that after the positive electrode 22, the separator 23, and the negative electrode 21 are stacked in sequence, ultrasonic waves are used to weld the tabs 13 of the negative electrode 21 together. Since ultrasonic welding uses high-frequency vibration energy to cause the surfaces of the materials to be welded to rub against each other, thereby generating heat, and achieving the connection of the materials under pressure.

[0085] Therefore, when the negative electrode tabs 13 are welded together, the vibration acting on the negative electrode sheet 21 can easily cause damage or even breakage to the negative electrode sheets 21 located at the beginning and end of the stacking direction. Based on this, in this embodiment, the thickness D3 of the negative electrode sheets 21 located at the beginning and end is set to be larger, thereby improving the strength of the negative electrode sheets 21 located at the beginning and end, so as to avoid damage to them during the welding process.

[0086] In one embodiment, 12μm≤D3≤30μm, 4μm≤D4≤12μm. This ensures that the negative electrode 21 located at the beginning and end positions, as well as other negative electrode 21 located between the beginning and end positions, all have suitable thickness dimensions, so as to ensure smooth welding while controlling the material cost of the negative electrode 21.

[0087] Among them, thickness D3 includes but is not limited to 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm , 23μm, 24μm, 25μm, 30μm, 14.5μm, 17.5μm, 20.5μm, 23.5μm, 26.5μm, 28.5μm, 30μm.

[0088] Thickness D4 includes but is not limited to 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 11μm, 12μm, 4.8μm, 6.2μm, 7.8μm, 9.2μm, 10.8μm, 12μm.

[0089] Please refer to Figure 9, which is a schematic diagram of the structure of a battery cell 3 provided in an embodiment of this application. The battery cell 3 includes a housing 31 and an electrode assembly 2 provided in some embodiments of this application. The electrode assembly 2 is disposed within the housing 31. One of the positive electrode plate 22 and the negative electrode plate 21 is electrically connected to the housing 31, and the other is electrically connected to an electrode post disposed on the housing 31.

[0090] Specifically, the negative electrode 21 is electrically connected to the outer casing 31, while the positive electrode 22 is insulated from the outer casing 31.

[0091] Specifically, a positive terminal 32 is provided on the outer casing 31, and the positive terminal 32 is insulated from the outer casing 31. The tab 13 of the positive electrode plate 22 is electrically connected to the positive terminal 32.

[0092] Furthermore, rounded corners are provided on the positive electrode 22 and negative electrode 21 at the corners corresponding to the outer casing 31. The rounded corners on the negative electrode 21 and positive electrode 22 have the same diameter as the adjacent rounded corners on the inner wall of the outer casing 31, ensuring that the circumference of the rounded corners on the negative electrode 21 and positive electrode 22 closely matches the circumference of the adjacent rounded corners on the inner wall of the outer casing 31. This allows for sufficient contact between the electrode assembly 2 and the inner wall of the outer casing 31, thereby increasing the size of the inner cavity occupied by the electrode assembly 2 and improving capacity density. Moreover, it ensures that the electrode assembly 2 experiences uniform stress when the cell 3 is subjected to various vibrations, impacts, or other safety risks, thus reducing the risk of deformation and cracking of the positive electrode 22 and negative electrode 21.

[0093] Among them, cell 3 is used in consumer electronics products, such as smartwatches and AR glasses.

[0094] In the embodiments of this application, by employing the electrode assembly 2 provided in some embodiments of this application, the amount of active material layer 12 of the electrode 1 can be increased, thereby improving the energy density of the battery cell 3. The technical solutions and effects of this application will be described in detail below through specific embodiments. These embodiments are merely some examples of this application and are not intended to limit the scope of this application.

[0095] This embodiment aims to examine the impact of applying electrode sheets to cell 3 on the capacity of cell 3.

[0096] The specific details of the test content for the embodiment are as follows:

[0097] I. Test-related instructions

[0098] The equipment used for testing is a power battery tester, model CTE-8008-5V200A.

[0099] The test environment temperature was 25±2℃.

[0100] Test subject 1: A battery cell from a related technology, with a length of 45mm, a width of 10mm, a thickness of 3.2mm, and a volume of 1440mm². 3 .

[0101] Test Subject 2: The battery cell 3 provided in the embodiments of this application has a length of 45mm, a width of 10mm, a thickness of 3.2mm, and a volume of 1440mm². 3 .

[0102] II. Testing.

[0103] A capacity test was performed on test object 1, and the 0.2 capacity of test object 1 was found to be 209mAh.

[0104] The capacity test of test object 2 was carried out, and the capacity of test object 2 at 0.2 was found to be 215mAh.

[0105] III. Comparison Explanation.

[0106] The test results show that, for the same volume, the capacity of the battery cell 3 provided in the embodiments of this application is greater than that of the battery cells in the related technologies, and the capacity of the battery cell 3 provided in the embodiments of this application is 2.9% greater than that of the battery cells in the related technologies. Therefore, it can be seen that the electrode 1 provided in the embodiments of this application can effectively increase the energy density of the battery cell 3.

[0107] Among them, 0.2c capacity refers to the specific value of the actual amount of electricity that the battery cell can hold after being charged and discharged with a current of 0.2 times the rated capacity to perform a capacity test on the battery cell.

Claims

1. An electrode (1), comprising: The current collector (11) includes a main body (111) and a protrusion (112) extending outward from the edge of the main body (111); An active material layer (12) is disposed on the main body (111) and the protrusion (112); The tab (13) is connected to the main body (111).

2. The electrode (1) according to claim 1, wherein, The main body (111) has a first edge Z (113) and a second edge Z (114) connected to each other. The first edge Z (113) and the second edge Z (114) are arranged at an angle. The protrusion (112) protrudes outward from a portion of the first edge Z (113), and the protrusion (112) has two first edges B (116) extending along the protrusion direction, one of which is collinear with the second edge Z (114).

3. The electrode (1) according to claim 2, wherein, The first edge B (116), which is away from the second edge Z (114), forms an obtuse angle α with the first edge Z (113), satisfying: 90°<α≤135°.

4. The electrode (1) according to any one of claims 1-3, wherein, The distance H between the side of the protrusion (112) away from the body (111) and the edge of the body (111) connected to it satisfies: 0 < H ≤ 2 mm.

5. The electrode (1) according to any one of claims 1-4, wherein, The main body (111) has a third edge Z (115), a first edge Z (113) and a second edge Z (114) connected in sequence, and the third edge Z (115) and the second edge Z (114) are both set at an angle to the first edge Z (113); The tab (13) is connected to the first edge Z (113), and the distance between the tab (13) and the third edge Z (115) is not equal to the distance between the tab (13) and the second edge Z (114).

6. The electrode (1) according to claim 5, wherein, The minimum distance between the tab (13) and the third edge Z (115) is dmin1, 0≤dmin1≤20mm, or the minimum distance between the tab (13) and the second edge Z (114) is dmin2, 0≤dmin2≤20mm.

7. The electrode (1) according to claim 5 or 6, wherein, The distance between the tab (13) and the third edge Z (115) is d1, and the distance between the tab (13) and the second edge Z (114) is d2, satisfying: |d1-d2|≥2mm.

8. The electrode (1) according to any one of claims 1-7, wherein, The main body (111) has a first edge Z (113) and a third edge Z (115) connected to each other. The first edge Z (113) and the third edge Z (115) are set at an angle. One side of the tab (13) is connected to the first edge Z (113). Along the extension direction of the tab (13), the tab (13) has two extending edges (131), one of which is collinear with the third edge Z (115).

9. The electrode (1) according to any one of claims 1-8, wherein, The connection between the electrode tab (13) and the current collector (11) has a first corner (14), and a rounded corner R1 is provided at the first corner (14). The other corners of the electrode (1) are provided with rounded corners R2. The radius of the rounded corner R1 is greater than the radius of the rounded corner R2. The radius of at least one of the fillet R1 and the fillet R2 is gradually changed.

10. The electrode (1) according to any one of claims 1-9, wherein, The tab (13) and the protrusion (112) are located on the same side of the body (111).

11. An electrode assembly (2), comprising: Multiple negative electrode plates (21); Multiple positive electrode plates (22) are arranged alternately and stacked with the multiple negative electrode plates (21) in sequence; Multiple diaphragms (23) are used to insulate and isolate two adjacent positive electrode plates (22) and negative electrode plates (21); The negative electrode (21) is the electrode (1) according to any one of claims 1-10.

12. The electrode assembly (2) according to claim 11, wherein, The positive electrode (22) has a positive electrode tab (221), which is disposed opposite to the protrusion (112) along the stacking direction.

13. The electrode assembly (2) according to claim 12, wherein, The positive electrode tab (221) has a width dimension W1, and in the direction of the width dimension W1 of the positive electrode tab (221), the protrusion (112) has a dimension W2, satisfying: W2 > W1.

14. The electrode assembly (2) according to any one of claims 11-13, wherein, Along the stacking direction, the thickness of the positive electrode (22) located at the first and last positions is D1, and the thickness of the remaining positive electrode (22) is D2, satisfying: D1 > D2.

15. The electrode assembly (2) according to claim 14, wherein, 16μm≤D1≤25μm, 6μm≤D2≤12m.

16. The electrode assembly (2) according to any one of claims 11-15, wherein, Along the stacking direction, the thickness of the negative electrode (21) located at the first and last positions is D3, and the thickness of the remaining negative electrode (21) is D4, satisfying: D3 > D4.

17. The electrode assembly (2) according to claim 16, wherein, 12μm≤D3≤30μm, 4μm≤D4≤12m.

18. A battery cell (3), comprising: Outer shell (31); And, the electrode assembly (2) as described in any one of claims 11-17 is disposed within the housing.

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