Pole piece and battery cell

Abstract

The utility model relates to the technical field of batteries, and particularly provides a pole piece and a battery cell. The pole piece comprises a current collector and an active substance layer arranged on the current collector, the active material layer comprises a frame area and an in-frame area, a plurality of concave parts arranged at intervals are arranged in the in-frame area, and the frame area comprises a convex frame which is located on the edge of the in-frame area and arranged in the circumferential direction of the in-frame area. The electrode plate can significantly increase the effective surface area of the active material layer, provide a larger contact area between an electrode material and an electrolyte, improve the contact efficiency between the electrode material and lithium ions, and promote the diffusion and migration of the lithium ions in the electrode plate, thereby improving the energy density and power density of the battery, and improving the service life of the battery. The charge-discharge speed and the cycle stability of the battery are improved, the polarization phenomenon of the electrode plate is reduced, and the use performance of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pole piece and a battery cell. Background Art

[0002] The application of power batteries is becoming more and more extensive. Some larger equipment such as automobiles and construction machinery have gradually begun to use batteries as power energy. The battery life and battery size are important factors affecting the usability of these electric devices. Therefore, improving the battery performance such as charging and discharging speed, cycle stability, energy density, etc. has always been a research direction in the battery field. Utility Model Content

[0003] In view of this, the embodiments of the present application are directed to providing a pole piece and a battery cell including the pole piece, aiming to improve the performance of the battery.

[0004] The present application provides a pole piece, comprising a current collector and an active material layer arranged on the current collector; the active material layer comprises a border area and an inner-frame area, the inner-frame area has a plurality of recessed portions arranged at intervals, and the border area comprises a convex border located at the edge of the inner-frame area, arranged along the circumference of the inner-frame area.

[0005] In a possible embodiment, the frame includes first protrusions arranged at intervals along a first direction and second protrusions arranged at intervals along a second direction; in the inner area of ​​the frame, a protrusion is between two adjacent recessed portions, and the recessed portions and / or the protruding portions extend along the second direction and are arranged alternately in sequence along the first direction.

[0006] In a possible implementation, in the thickness direction, the thickness of the first protrusion is greater than the thickness of the protruding portion, and the thickness difference is 80 μm to 180 μm; and / or the thickness of the second protrusion is greater than the thickness of the protruding portion, and the thickness difference is 50 μm to 150 μm;

[0007] and / or, the thickness of the first protrusion is greater than the thickness of the second protrusion, and the thickness difference is 10 μm to 50 μm;

[0008] And / or, the junction between the first protrusion and the second protrusion is a corner area, and the thickness of the corner area is 250 μm to 290 μm.

[0009] In a possible implementation, the width of the protrusion in the first direction is 600 μm to 610 μm; and / or the width of the recess in the first direction is 320 μm to 330 μm; and / or the width difference between the protrusion and the recess in the first direction is 270 μm to 290 μm.

[0010] In a possible implementation, the width of the first protrusion in the first direction gradually decreases along the thickness direction gradually away from the current collector; and / or the width of the second protrusion in the first direction gradually decreases along the thickness direction gradually approaching the current collector.

[0011] In a possible implementation, the width of the protrusion in the first direction gradually decreases along the thickness direction gradually away from the current collector; and / or the width of the protrusion in the first direction gradually decreases along the thickness direction gradually approaching the current collector.

[0012] In a possible implementation manner, the cross section of the recessed portion is arc-shaped; and / or the cross sections of two ends of the recessed portion in the second direction are arc-shaped.

[0013] In a possible implementation manner, a distance between an end edge of the recessed portion in the second direction and an end edge of the pole piece on the same side is 0.15 mm to 0.2 mm.

[0014] In a possible implementation, in the thickness direction, the active material layer includes a first layer segment and a second layer segment, the recessed portion, the raised portion, the first raised portion, and the second raised portion are all located in the second layer segment, the thickness value of the first layer segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, and the thickness value from the highest point of the raised portion to the current collector is d3, wherein:

[0015] 80μm≤d0≤90μm; and / or, 220μm≤d1≤225μm; and / or, 105μm≤d2≤110μm; and / or, 120μm≤d3≤130μm.

[0016] In a possible implementation, in the thickness direction, the active material layer includes a first layer segment and a second layer segment, the recessed portion, the raised portion, the first raised portion, and the second raised portion are all located in the second layer segment, the thickness value of the first layer segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, the thickness value from the highest point of the raised portion to the current collector is d3, the difference between d1 and d0 is L1, the difference between d2 and d0 is L2, and the difference between d3 and d0 is L3, wherein:

[0017] 130μm≤L1≤145μm; and / or, 15μm≤L2≤30μm; and / or, 30μm≤L3≤50μm.

[0018] In a possible implementation, in the thickness direction, the active material layer includes a first layer segment and a second layer segment, the recessed portion, the raised portion, the first raised portion, and the second raised portion are all located in the second layer segment, the thickness value of the first layer segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, the thickness value from the highest point of the raised portion to the current collector is d3, the difference between d1 and d0 is L1, the difference between d2 and d0 is L2, and the difference between d3 and d0 is L3, wherein:

[0019] 100μm≤L1-L2≤130μm; and / or, 1≤L1 / L3≤5

[0020] The present application also provides a battery cell, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet and / or the negative electrode sheet is a electrode sheet as described in any one of the above items, and the bonding force between the frame area of ​​the electrode sheet and the separator is greater than the bonding force between the inner frame area and the separator.

[0021] The electrode provided in the present application has an uneven surface of the active material layer, which can form a surface similar to a wave or scale shape, and a protrusion is arranged in the outermost area to form a frame structure. Compared with the plane surface of the active material layer in the prior art, on the one hand, the effective surface area of ​​the active material layer can be significantly increased, and even in the case of the same amount of active material, the effective surface area of ​​the active material layer can be increased, providing a larger contact area between the electrode material and the electrolyte, and improving the contact efficiency between the electrode material and the lithium ions, thereby improving the energy density and power density of the battery; and the protrusions and depressions are arranged in an arranged manner. The structure can form more ion transmission channels, promote the diffusion and migration of lithium ions in the electrode sheet, improve the charging and discharging speed and cycle stability of the battery, reduce the polarization phenomenon of the electrode sheet, and improve the performance of the battery; on the other hand, during the charging and discharging process of the lithium battery, the electrode sheet may yield and crack, and the setting of the frame structure in the present application can increase the strength and structural stability of the electrode sheet, effectively disperse and alleviate the stress generated by the electrode sheet during the charging and discharging process, improve the durability and reliability of the electrode sheet, thereby reducing the damage and life attenuation of the battery caused by volume expansion, and improving the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure shows a schematic diagram of the structure of the pole piece at a first angle in an embodiment of the present application;

[0023] Figure 2 The figure shows a schematic diagram of the structure of the pole piece at the second angle in the embodiment of the present application;

[0024] Figure 3The figure shows a schematic diagram of the structure of the pole piece in the embodiment of the present application at a cross-sectional perspective;

[0025] Figure 4 Shown is a schematic diagram of the layer segments of the active material layer in the embodiment of the present application.

[0026] Figure 1-Figure 4 middle:

[0027] 1. Current collector; 2. Active material layer; 21. First protrusion; 22. Second protrusion; 23. Protrusion; 24. Depression; 201. First layer segment; 202. Second layer segment. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] Please refer to the attached Figure 1-4 , an embodiment of the present application provides a pole piece, including a current collector 1 and an active material layer 2 arranged on the current collector 1; the active material layer 2 is laid on one side or both side surfaces of the current collector 1. At the same time, the surface of the active material layer 2 includes an inner frame area and a border area, the inner frame area has a plurality of recessed portions 24 arranged at intervals, and the area between two adjacent recessed portions 24 forms a raised portion 23, and the raised portions 23 and the recessed portions 24 are arranged alternately, for example, alternately arranged along the first direction or the second direction, or arranged in an array. At the same time, the border area includes a raised border arranged at the edge of the inner frame area, or it can be said that the edge of the inner frame area is provided with a protrusion, and the protrusion is arranged along the first direction and / or the second direction, for example, extending along the circumference of the inner frame area to form a border.

[0030] With such arrangement, the surface of the active material layer 2 is uneven and can form a surface similar to a wave or scale shape, and a frame structure is arranged in the outermost area. Compared with the prior art in which the surface of the active material layer 2 is a plane, on the first hand, the effective surface area of ​​the active material layer 2 can be significantly increased. Even in the case of the same amount of active material, the effective surface area of ​​the active material layer 2 can be increased, providing a larger contact area between the electrode material and the electrolyte, improving the contact efficiency between the electrode material and the lithium ions, thereby improving the energy density and power density of the battery; and the structure in which the protrusions and depressions are arranged can form more ion transmission channels, promote the diffusion and migration of lithium ions in the electrode sheet, improve the charge and discharge speed and cycle stability of the battery, reduce the polarization phenomenon of the electrode sheet, and improve the performance of the battery; on the second hand On the one hand, the structure of the outermost edge of the active material is a frame structure, which is conducive to gathering more electrolyte in the frame area, accelerating the ion transmission of the active material and the electrolyte, and improving the charging and discharging efficiency; on the third hand, during the charging and discharging process of the lithium battery, the electrode may yield and crack, and the edge of the active material layer 2 is a raised structure. When the electrode and the diaphragm are combined into a battery cell, more space can be made on the side of the active material layer 2, providing relief space for the volume expansion of the electrode during the charging and discharging cycle, effectively dispersing and alleviating the stress and pressure generated by the volume expansion of the electrode, and the structure of the staggered arrangement of the raised portion 23 and the recessed portion 24 can also increase the strength and structural stability of the electrode, improve the durability and reliability of the electrode, thereby reducing the damage and life attenuation of the battery caused by volume expansion, and improving the service life of the battery.

[0031] like Figure 1 As shown, the active material layer 2 includes a frame-shaped frame area and an inner frame area located inside the frame area. The frame in the frame area is arranged along the circumference of the inner frame area. The frame may include at least two first protrusions 21 and at least two second protrusions 22. The first protrusions 21 extend along the second direction and are arranged at intervals along the first direction. The second protrusions 22 extend in the first direction and are arranged at intervals along the second direction. The first protrusions 21 and the second protrusions 22 may be strip-shaped and may be connected end to end in the circumferential direction to form a closed annular frame; or, any one or more of the first protrusions 21 and the second protrusions 22 may be formed by arranging multiple strips (i.e., not a continuous long strip, but a long strip formed by arranging multiple strips along the extension direction). In this way, the first protrusions 21 and the second protrusions 22 may enclose a non-closed annular frame with a gap. The multiple recessed portions 24 and the multiple raised portions 23 are located in the inner frame area. In other words, the inner frame area is provided with multiple recessed portions 24 and multiple raised portions 23, and the multiple recessed portions 24 and the multiple raised portions 23 are alternately arranged in the frame enclosed by the first protrusion 21 and the second protrusion 22.

[0032] In the inner area of ​​the frame, the plurality of protrusions 23 and the plurality of depressions 24 may be arranged in a staggered manner in a regular pattern or in an array. In some embodiments shown in the present application, the depressions 24 and the protrusions 23 extend along the second direction and are arranged in a staggered manner in sequence along the first direction. Figure 1 As shown, the recessed portions 24 and the raised portions 23 are both in the shape of strips and are arranged alternately along the first direction to form a wave-like surface of the active material layer 2. Not only are the arrangements regular and convenient for production, but also, compared with setting hole-shaped pits on the surface of the active material layer 2, the effective surface area of ​​the electrolyte and the electrode material is further increased. Moreover, the recessed portions 24 are long strips, and the raised portions 23 are also long strips, so the transmission surface formed is wider, which is more conducive to the rapid transmission of ions, and further improves the charge and discharge efficiency.

[0033] In the inner region of the frame, the surface of the active material layer 2 may be entirely composed of the recessed portions 24 and the raised portions 23, such as Figure 1 and Figure 2 As shown, in the preferred embodiment shown in the present application, there are only recessed parts 24 and raised parts 23 in the inner area of ​​the frame. Of course, in some other embodiments, in addition to the recessed parts 24 and raised parts 23, there is also a flat part, which is higher than the recessed parts 24 and lower than the raised parts 23 in the thickness direction, and the surface can be a plane. For example, when the recessed parts 24 and the raised parts 23 are both strips extending along the second direction, the flat part can also be a strip extending along the second direction, and the flat part can be located between each adjacent raised part 23 and recessed part 24, or can be located at the edge of the inner area of ​​the frame and connected to the first protrusion 21. Of course, in some other embodiments not shown in the drawings of the present application, the raised parts 23 and the recessed parts 24 can also be discontinuous strips, or can be discontinuous strips formed by multiple strip segments arranged along the second direction. In such embodiments, the discontinuity between two adjacent strip segments is the flat part.

[0034] In some embodiments, in the thickness direction, the thickness of the first protrusion 21 is greater than the thickness of the protrusion 23, for example, the thickness difference is 80μm to 180μm, specifically 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, etc., or other values ​​not listed but within the range of 80μm to 180μm.

[0035] Similarly, in some embodiments, the thickness of the second protrusion 22 is greater than the thickness of the protrusion 23, such as the thickness difference is 50μm to 150μm; specifically, it can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, etc., or it can be other values ​​not listed but in the range of 80μm to 180μm.

[0036] Making the thickness of the first protrusion 21 and / or the second protrusion 22 in the border area greater than the thickness of the protrusion 23 in the inner frame area is equivalent to making the border area higher than the inner frame area. On the one hand, it is beneficial to gather more electrolyte in the inner frame area, accelerate the ion transmission of active substances and electrolytes, and enhance the efficiency and stability of battery charging and discharging; on the other hand, it can increase the amount of active substances at the edge of the pole piece, reduce the polarization or lithium precipitation of the pole piece, and improve the performance and service life of the battery; on the other hand, the protrusion at the edge of the active material layer 2 is the highest. When the pole piece and the diaphragm are combined into a battery cell, more space can be provided on the side of the active material layer 2, providing relief space for the volume expansion of the pole piece during the charge and discharge cycle, and relieving the stress and pressure of the pole piece caused by the volume expansion.

[0037] The thickness of the first protrusion 21 and the second protrusion 22 may be equal. Alternatively, in some embodiments, the thickness of the first protrusion 21 is greater than the thickness of the second protrusion 22, for example, the thickness difference is 10 μm to 50 μm, specifically, 10 μm, 15 μm, 18 μm, 20 μm, 25 μm, 28 μm, 30 μm, 35 μm, 38 μm, 40 μm, 45 μm, 48 μm, 50 μm, etc., or other values ​​not listed but within the range of 10 μm to 50 μm. The first protrusion 21, the protrusion 23 and the recessed portion 24 are arranged in the same direction and are located on both sides of all the protrusions 23 and the recessed portions 24 in the first direction. The second protrusion 22 is located on both sides of the inner frame area in the second direction. The first protrusion 21 is thicker than the second protrusion 22, so that more active materials can be arranged in the same direction, which is more conducive to ion transmission. At the same time, the thickness difference between the two is limited, so that the thickness difference is smaller, thereby improving the consistency of the thickness of each area of ​​the electrode piece and making the electrode piece and the diaphragm fit better.

[0038] In some embodiments, the junction of the first protrusion 21 and the second protrusion 22 is a corner area, and at least one corner area is the area with the largest thickness among all areas of the active material layer 2. For example, the thickness of the corner area is 250μm to 290μm. The junction of the first protrusion 21 and the second protrusion 22 is the corner area of ​​the active material layer 2, which is also the corner area of ​​the pole piece. The polarization and lithium precipitation phenomena in the corner area are the most serious. In this embodiment, the thickness of the active material layer 2 in the corner area is set to the thickest, which can reduce the polarization and lithium precipitation phenomena and improve the charge and discharge cycle performance and service life of the battery.

[0039] like Figure 1 and 3 As shown, in some embodiments, the width of the first protrusion 21 in the first direction gradually decreases along the thickness direction gradually away from the current collector 1. Similarly, in some embodiments, the width of the second protrusion 22 in the first direction gradually decreases along the direction gradually approaching the current collector 1. In some embodiments, the width of the protrusion 23 in the first direction gradually decreases along the thickness direction gradually away from the current collector 1. In some embodiments, the width of the protrusion 23 in the first direction gradually decreases along the thickness direction gradually approaching the current collector 1.

[0040] When the electrode is produced, the active material is in a slurry state and needs to be coated or sprayed onto the current collector 1 so that the first protrusion 21 / the second protrusion 22 / the protrusion 23 / the recessed portion 24 gradually narrows along the protrusion / recessed direction, which is very convenient for coating the active material in a slurry state onto the current collector 1 and speeds up the production efficiency; moreover, the surface of the active material layer 2 can be made closer to a smooth wavy shape, which is beneficial to the flow of the electrolyte, and is beneficial to increasing the ion transfer rate, thereby improving the charge and discharge efficiency of the battery.

[0041] Some specific embodiments are listed as follows. In some embodiments, the first protrusion 21 includes a first top surface.

[0042] and the first side surfaces located on both sides of the first top surface, the first top surface is a plane, and the first side surface is a plane or an arcuate surface, that is, the cross-section of the first protrusion 21 can be an arc or a trapezoid, or the shape of the first protrusion 21 can also be a combination of a plane and an arcuate surface.

[0043] In some embodiments, the second protrusion 22 includes a second top surface and second side surfaces located on both sides of the second top surface, the second top surface is a plane, and the second side surfaces are planes or arcuate surfaces. That is, the cross section of the second protrusion 22 can be an arcuate shape or a trapezoid, or the shape of the second protrusion 22 can also be a combination of a plane and an arcuate surface.

[0044] The protrusion 23 includes a third top surface, the recessed portion 24 includes a bottom surface, and a third side surface is between the third top surface and the bottom surface. The third side surface is both the side surface of the protrusion 23 and the side surface of the recessed portion 24. In some embodiments, the third top surface is a plane, the bottom surface is a plane or an arc surface, and the third side surface is a plane or an arc surface. That is, the cross-section of the protrusion 23 and the recessed portion 24 can be as follows: Figure 3 As shown, it can also be Figure 4 shown.

[0045] The cross-sections of the concave portion 24 and the convex portion 23 may be arc-shaped, trapezoidal, or trapezoidal with rounded corners.

[0046] In some embodiments, at least the cross-sections of the two ends of the recessed portion 24 in the second direction are arc-shaped. Such a configuration can not only increase the effective surface area of ​​the electrode sheet, which is conducive to improving the energy density of the battery, but also avoid the existence of unfavorable areas such as dead corners and narrow gaps that are not conducive to the flow of electrolyte, and avoid affecting the ion transmission between the positive and negative electrode sheets.

[0047] In some embodiments, the width of the protrusion 23 in the first direction is 600μm to 610μm, such as 601μm, 602μm, 603μm, 604μm, 605μm, 606μm, 607μm, 608μm, 609μm, 610μm, etc., or other values ​​not listed but within the range of 600μm to 610μm.

[0048] In some embodiments, the width of the recess 24 in the first direction is 320 μm to 330 μm, such as 321 μm, 322 μm, 323 μm, 324 μm, 325 μm, 326 μm, 327 μm, 328 μm, 329 μm, 330 μm, etc., or other values ​​not listed but within the range of 320 μm to 330 μm.

[0049] It should be noted that, in the above embodiments, the width value refers to the distance between the two side edges / side surfaces at the edge of the first protrusion 21 / the second protrusion 22 / the protruding portion 23 / the recessed portion 24 in the first direction, which can also be said to be the dimension at the widest point, or the dimension value of the projection in the thickness direction in the first direction.

[0050] In some embodiments, the width difference between the protrusion 23 and the recess 24 in the first direction is 270 μm to 290 μm. The width of the protrusion 23 is greater than the width of the recess 24, which is beneficial to increase the total amount of active material and improve the energy density of the battery. At the same time, the difference between the two is limited to avoid excessive width difference, which affects the effectiveness of setting the recess 24, and also makes the overall structure of the pole piece balanced and stable, improving stability.

[0051] In some embodiments, the distance between the end edge of the recessed portion 24 in the second direction and the end edge on the same side of the pole piece is 0.15 mm to 0.2 mm.

[0052] In some embodiments, Figure 4 As shown, in the thickness direction, the active material layer 2 includes a first layer segment 201 and a second layer segment 202, the recessed portion 24, the raised portion 23, the first raised portion 21 and the second raised portion 22 are all located in the second layer segment 202, the thickness value of the first layer segment 201 (the size in the thickness direction, the same below) is d0, the thickness value from the highest point of the first raised portion 21 to the current collector 1 is d1, the thickness value from the lowest point of the recessed portion 24 to the current collector 1 is d2, the thickness value from the highest point of the raised portion 23 to the current collector 1 is d3, the difference between d1 and d0 is L1, the difference between d2 and d0 is L2, and the difference between d3 and d0 is L3, wherein:

[0053] 80 μm ≤ d0 ≤ 90 μm; and / or, 220 μm ≤ d1 ≤ 225 μm; and / or, 105 μm ≤ d2 ≤ 110 μm; and / or, 120 μm ≤ d3 ≤ 130 μm;

[0054] and / or, 130 μm ≤ L1 ≤ 145 μm; and / or, 15 μm ≤ L2 ≤ 30 μm; and / or, 30 μm ≤ L3 ≤ 50 μm;

[0055] And / or, 100μm≤L1-L2≤130μm; and / or, 1≤L1 / L3≤5.

[0056] In this way, through the above-mentioned parameter settings, the active material layer 2 forms a structure in which depressions and protrusions are arranged alternately. At the same time, in the actual production process, the thickness of each part can be set more accurately, so that the thickness of each protrusion 23 is consistent, the thickness of each depression 24 is consistent, and the first protrusion 21 is slightly higher but the thickness difference is small, which is beneficial to promoting ion transmission and at the same time can improve the overall thickness consistency of the electrode piece, avoid large production errors in various parts, improve the quality of the electrode piece, and also improve the fit between the electrode piece and the diaphragm.

[0057] The embodiment of the present application further provides a battery, comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and / or the negative electrode sheet is the electrode sheet as described in any of the above embodiments. Then the battery has the beneficial effects described in the above embodiments, which will not be described one by one here.

[0058] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0059] The components and devices involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As will be appreciated by those skilled in the art, these components and devices can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0060] It should also be noted that in the device and apparatus of the present application, each component can be decomposed and / or reassembled, and such decomposition and / or reassembly should be regarded as an equivalent solution of the present application.

[0061] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0062] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

[0063] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A pole piece, characterized in that: comprising a current collector and an active material layer disposed on the current collector; The active material layer includes a frame area and an inner frame area, wherein the inner frame area has a plurality of recessed portions arranged at intervals, and the frame area includes a convex frame located at the edge of the inner frame area and arranged along the circumference of the inner frame area.

2. The pole piece according to claim 1, characterized in that: The frame includes first protrusions arranged at intervals along the first direction and second protrusions arranged at intervals along the second direction; in the inner area of ​​the frame, there is a protrusion between two adjacent recesses, and the recesses and / or the protrusions extend along the second direction and are arranged alternately in sequence along the first direction.

3. The pole piece according to claim 2, characterized in that: In the thickness direction, the thickness of the first protrusion is greater than the thickness of the protrusion portion, and the thickness difference is 80 μm to 180 μm; and / or, The thickness of the second protrusion is greater than the thickness of the protrusion portion, and the thickness difference is 50 μm to 150 μm; and / or, the thickness of the first protrusion is greater than the thickness of the second protrusion, and the thickness difference is 10 μm to 50 μm; And / or, the junction between the first protrusion and the second protrusion is a corner area, and the thickness of the corner area is 250 μm to 290 μm.

4. The pole piece according to claim 2, characterized in that: The width of the protrusion in the first direction is 600 μm to 610 μm; And / or, the width of the recessed portion in the first direction is 320 μm to 330 μm; And / or, a width difference between the protrusion and the depression in the first direction is 270 μm to 290 μm.

5. The pole piece according to claim 2, characterized in that: Along the thickness direction away from the current collector, the width of the first protrusion in the first direction gradually decreases; and / or, along the thickness direction close to the current collector, the width of the second protrusion in the first direction gradually decreases.

6. The pole piece according to claim 2, characterized in that: Along the thickness direction away from the current collector, the width of the protrusion in the first direction gradually decreases; and / or, along the thickness direction close to the current collector, the width of the protrusion in the first direction gradually decreases.

7. The pole piece according to claim 1, characterized in that: The cross section of the recessed portion is arc-shaped; and / or the cross sections of two ends of the recessed portion in the second direction are arc-shaped.

8. The pole piece according to claim 1, characterized in that: The distance between the end edge of the recessed portion in the second direction and the end edge on the same side of the pole piece is 0.15 mm to 0.2 mm.

9. The pole piece according to claim 2, characterized in that: In the thickness direction, the active material layer includes a first layer segment and a second layer segment, the recessed portion, the raised portion, the first raised portion, and the second raised portion are all located in the second layer segment, the thickness value of the first layer segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, and the thickness value from the highest point of the raised portion to the current collector is d3, wherein: 80μm≤d0≤90μm; and / or, 220μm≤d1≤225μm; and / or, 105μm≤d2≤110μm; and / or, 120μm≤d3≤130μm.

10. The pole piece according to claim 2, characterized in that: In the thickness direction, the active material layer includes a first segment and a second segment, the recessed portion, the raised portion, the first raised portion and the second raised portion are all located in the second segment, the thickness value of the first segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, the thickness value from the highest point of the raised portion to the current collector is d3, the difference between d1 and d0 is L1, the difference between d2 and d0 is L2, and the difference between d3 and d0 is L3, wherein: 130μm≤L1≤145μm; and / or, 15μm≤L2≤30μm; and / or, 30μm≤L3≤50μm.

11. The pole piece according to claim 2, characterized in that: In the thickness direction, the active material layer includes a first segment and a second segment, the recessed portion, the raised portion, the first raised portion and the second raised portion are all located in the second segment, the thickness value of the first segment is d0, the thickness value from the highest point of the first raised portion to the current collector is d1, the thickness value from the lowest point of the recessed portion to the current collector is d2, the thickness value from the highest point of the raised portion to the current collector is d3, the difference between d1 and d0 is L1, the difference between d2 and d0 is L2, and the difference between d3 and d0 is L3, wherein: 100μm≤L1-L2≤130μm; and / or, 1≤L1 / L3≤5.

12. A battery cell, characterized in that: It comprises a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet and / or the negative electrode sheet is the electrode sheet according to any one of claims 1 to 11, and the bonding force between the frame area of ​​the electrode sheet and the separator is greater than the bonding force between the inner frame area and the separator.

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