Electrode sheet, battery cell and battery

Abstract

An electrode sheet, a battery cell and a battery. A first chamfer comprises a first arc section and at least one first transition section, the first arc section is connected to a first side edge and / or a second side edge by means of the first transition section, and the first arc section protrudes in a direction moving away from the center of the electrode sheet, so as to avoid the problem in the related art that the corners of the electrode sheet are acute angles, obtuse angles or right angles, thereby effectively preventing the corners of the electrode sheet piercing a separator.

Description

A pole piece, a battery cell and a battery

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 27, 2023, with application number 2023216615369. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a pole piece, a battery cell and a battery. Background Art

[0003] Lithium batteries refer to batteries that contain lithium (including metallic lithium, lithium alloys, lithium ions, and lithium polymers) in their electrochemical system. Lithium batteries have the advantages of high energy density, good cycle performance, and long service life, and are widely used in products such as electric equipment, electrical appliances, and intelligent machines. Lithium batteries can be divided into cylindrical lithium-ion batteries, soft-pack polymer lithium-ion batteries, and prismatic lithium-ion batteries according to their structure. The pole pieces of cylindrical lithium-ion battery cells are assembled in a winding manner; the battery cells of soft-pack polymer and prismatic lithium-ion batteries are assembled in a winding manner or in a stacking manner.

[0004] Compared with the winding method, lithium batteries formed by the stacking method have better rate performance and liquid absorption processing performance, so they have become the mainstream method of assembling cells for soft-pack polymer and square lithium-ion batteries. At present, before the lithium-ion battery cells are assembled using the stacking method, in order to prevent the pole pieces from shaking due to external impact and thus causing the pole pieces to pierce the diaphragm, the corners of the pole pieces are usually made into V-shaped angles. Although the above method reduces the risk of the pole pieces piercing the diaphragm to a certain extent, it does not completely eliminate the right angle of the pole piece, but only reduces or shifts the right angle. Therefore, the risk of the pole piece piercing the diaphragm still exists in the relevant technology. SUMMARY OF THE INVENTION

[0005] The embodiments of the present application provide a pole piece, a battery cell, and a battery, which are used to solve or at least partially solve the problem that the battery is shaken by external impact, causing the corners of the pole piece to pierce the diaphragm.

[0006] In a first aspect, an embodiment of the present application provides a pole piece, comprising:

[0007] A pole piece body, the pole piece body comprising a first side and a second side connected to each other, wherein a first chamfer is provided at a connection between the first side and the second side;

[0008] The first chamfer includes a first arc segment and at least one first transition segment, the first arc segment is connected to the first side and / or the second side through the first transition segment, and the first arc segment protrudes in a direction away from the center of the pole piece body.

[0009] In a second aspect, an embodiment of the present application provides a battery cell comprising a positive electrode sheet, a negative electrode sheet, and a separator arranged between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet comprises the electrode sheet described in the above section, and the negative electrode sheet comprises the electrode sheet described in the above section.

[0010] In a third aspect, an embodiment of the present application provides a battery, comprising a shell and any of the above-mentioned battery cells, wherein the shell has a receiving cavity, and the battery cell is located in the receiving cavity.

[0011] Beneficial effects of the embodiments of the present application: The embodiments of the present application disclose a pole piece, a battery cell and a battery, wherein the pole piece includes a pole piece body, the pole piece body includes a first side and a second side connected to each other, and a first chamfer is provided at the connection between the first side and the second side; the first chamfer is provided to include a first arc segment and at least one first transition segment, the first arc segment is connected to the first side and / or the second side through the first transition segment, and the first arc segment protrudes in a direction away from the center of the pole piece body, thereby avoiding the problem that the edge corners of the pole piece in the related art are acute angles, obtuse angles or right angles, and effectively preventing the battery from shaking due to external force impact, which causes the edge corners of the pole piece to pierce the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is a schematic diagram of the structure of a pole piece provided in an embodiment of the present application;

[0013] FIG2 is a first enlarged view of point A in FIG1 ;

[0014] Figure 3 is an enlarged view of point B in Figure 1;

[0015] Figure 4 is an enlarged view of point C in Figure 1;

[0016] FIG5 is a second enlarged view of point A in FIG1 ;

[0017] FIG6 is a third enlarged view of point A in FIG1 .

[0018] Description of Reference Numerals

[0019] 1-pole piece; 10-pole piece body; 20-pole ear;

[0020] 100 - active material layer; 200 - ceramic coating; 210 - first ceramic coating; 220 - second ceramic coating;

[0021] 200A-spacer; 201A-overlapping portion;

[0022] 101-first chamfer; 201-second chamfer; 301-third chamfer;

[0023] 10A-first arc segment; 10B-first transition segment; 20A-second arc segment; 20B-second transition segment; 30A-third arc segment; 30B-third transition segment;

[0024] 11-first side; 12-second side; 21-third side; 22-fourth side; 23-fifth side;

[0025] 401 - first transition section; 402 - second transition section. Modes for Carrying Out the Invention

[0026] In the description of this application, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed or detachable connections, mechanical or electrical connections, direct or indirect connections through an intermediate medium, and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0027] In the description of this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] The present application provides a pole piece, a battery cell, and a battery. Each of these is described in detail below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments.

[0029] Please refer to Figures 1 to 6. This embodiment provides a pole piece, a battery cell and a battery. The pole piece 1 includes a pole piece body 10, and the pole piece body 10 includes a first side 11 and a second side 12 connected to each other. A first chamfer 101 is provided at the connection between the first side 11 and the second side 12; wherein, the first chamfer 101 includes a first arc segment 10A and at least one first transition segment 10B, and the first arc segment 10A is connected to the first side 11 and / or the second side 12 through the first transition segment 10B, and the first arc segment 10A protrudes in a direction away from the center of the pole piece body 10.

[0030] It should be noted that in the related art, before the lithium-ion battery cells are assembled in a stacking manner, in order to prevent the electrodes from shaking when impacted by external forces and causing the electrodes to pierce the diaphragm, the corners of the electrodes are usually made into V-shaped angles. Although the above method reduces the risk of the electrodes piercing the diaphragm to a certain extent, it does not completely eliminate the right angles of the electrodes, but only makes the right angles smaller or shifts their position. Therefore, the risk of the electrodes piercing the diaphragm still exists in the related art.

[0031] It can be understood that, in this embodiment, the first chamfer 101 is provided to include a first arc segment 10A and at least one first transition segment 10B, the first arc segment 10A is connected to the first side 11 and / or the second side 12 through the first transition segment 10B, and the first arc segment 10A protrudes in a direction away from the center of the pole piece body 10, thereby avoiding the problem in the related art that the corners of the pole piece are acute angles, obtuse angles or right angles, and effectively preventing the battery from shaking due to external impact, which causes the corners of the pole piece to pierce the diaphragm.

[0032] The technical solution of this application is now described in conjunction with specific embodiments.

[0033] Please refer to Figure 1 and Figure 2; Figure 1 is a structural schematic diagram of the pole piece provided in an embodiment of the present application; Figure 2 is a first enlarged view of point A in Figure 1.

[0034] In one embodiment, the pole piece 1 includes a pole piece body 10 , and the pole piece body 10 includes a first side 11 and a second side 12 connected to each other. A first chamfer 101 is provided at the connection between the first side 11 and the second side 12 .

[0035] Furthermore, the material of the pole piece 1 includes but is not limited to aluminum foil, the first chamfer 101 includes a first arc segment 10A and at least one first transition segment 10B, the first arc segment 10A is connected to the first side 11 and / or the second side 12 through the first transition segment 10B; further, the shape of the pole piece body 10 is polygonal, and each corner of the pole piece body 10 is provided with the first chamfer 101, the first chamfer 101 includes a first arc segment 10A and the first transition segments 10B distributed at both ends of the first arc segment 10A, the first arc segment 10A is connected to the first side 11 and the second side 12 through the first transition segment 10B, wherein the first arc segment 10A protrudes in a direction away from the center of the pole piece body 10; preferably, the first arc segment 10A is arranged tangent to the first transition segment 10B.

[0036] Among them, the shape of the pole piece body 10 is preferably rectangular, and the four corners of the pole piece body 10 are provided with the first chamfer 101; specifically, in this embodiment, the first arc segment 10A is a circular arc segment with a single curvature, and the first transition segment 10B is a straight line segment; the curvature radius of the first arc segment 10A is greater than or equal to 0.1 mm, and less than or equal to 30 mm; wherein, the curvature radius of the first arc segment 10A is preferably one of 5 mm, 10 mm, 15 mm or 20 mm; it can be understood that this embodiment alleviates the problem in the related art that the battery is shaken by external impact, causing the pole piece corners to pierce the diaphragm; and it is convenient for laser / ultrasonic cutting to form the above-mentioned first arc segment 10A, which is beneficial to the processing and forming of the pole piece and improves production efficiency.

[0037] It can be understood that in this embodiment, the shape of the pole piece body 10 is set to be rectangular, and the four corners of the pole piece body 10 are provided with the first chamfer 101. The first chamfer 101 includes a first arc segment 10A and the first transition segment 10B distributed at both ends of the first arc segment 10A. The first arc segment 10A is connected to the first side 11 and the second side 12 through the first transition segment 10B, thereby reducing the problem of the pole piece 1 being bumped during the stacking process, causing the corners to bend, and the material to fall off and produce dust.

[0038] At the same time, this embodiment sets the first arc segment 10A and the first transition segment 10B to be tangent, and the intersection of the side of the pole piece body 10 and the first chamfer 101 is smoothly transitioned, which effectively prevents the battery from shaking due to external impact, causing the edge of the pole piece 1 to pierce the diaphragm, thereby reducing the risk of the diaphragm being punctured; and the present application has a simple structure and low manufacturing difficulty.

[0039] Furthermore, in one embodiment, please refer to FIG1 and FIG3 ; FIG3 is an enlarged view of point B in FIG1 .

[0040] In this embodiment, the pole piece 1 also includes a pole ear 20, which is located on the first side 11. The pole ear 20 extends in a direction away from the pole piece body 10, and the pole ear 20 and the pole piece body 10 can be integrally formed by laser cutting, which has a streamlined structure and reduces the production cost of the pole piece 1.

[0041] Among them, the pole ear 20 includes a third side 21, a fourth side 22 and a fifth side 23, the third side 21 is away from the pole piece body 10, the fourth side 22 and the fifth side 23 are arranged opposite to each other, the fourth side 22 and the fifth side 23 are respectively connected to the two ends of the third side 21, and a second chamfer 201 is formed at the connection; thereby avoiding the problems in the prior art where the pole pieces collide during the lamination (battery production) and cause damage, folding, wrinkling and other problems to the pole ear.

[0042] Furthermore, the second chamfer 201 includes a second arc segment 20A and at least one second transition segment 20B; at the intersection of the fourth side 22 and the third side 21, the second arc segment 20A is connected to the fourth side 22 and / or the third side 21 through the second transition segment 20B; at the intersection of the fifth side 23 and the third side 21, the second arc segment 20A is connected to the fifth side 23 and / or the third side 21 through the second transition segment 20B; wherein, the second arc segment 20A protrudes away from the center of the tab 20, thereby reducing stress concentration and reducing the risk of breakage / tearing / damage of the tab 20.

[0043] In which, the second chamfer 201 includes a second arc segment 20A and a second transition segment 10B distributed at both ends of the second arc segment 20A, at the intersection of the fourth side 22 and the third side 21, the second arc segment 20A is connected to the fourth side 22 and the third side 21 through the second transition segment 20B, and at the intersection of the fifth side 23 and the third side 21, the second arc segment 20A is connected to the fifth side 23 and the third side 21 through the second transition segment 20B, wherein the second arc segment 20A protrudes in the direction away from the center of the pole lug 20; preferably, the second arc segment 20A and the second transition segment 20B are arranged tangent to each other, so that the side of the pole lug 20 and the second chamfer 201 have a smooth transition, further reducing the risk of the pole lug 20 being damaged or bent by external collision, and improving the rigidity of the pole lug 20; and the present application has a simple structure and low manufacturing difficulty.

[0044] Specifically, in this embodiment, the second arc segment 20A is a circular arc segment with a single curvature, and the second transition segment 20B is a straight line segment; the curvature radius of the second arc segment 20A is greater than or equal to 0.1 mm, and less than or equal to 25 mm; wherein, the curvature radius of the second arc segment 20A is preferably one of 8 mm, 14 mm or 20 mm. It can be understood that this embodiment better reduces stress concentration by setting the curvature radius of the second arc segment 20A to preferably one of 8 mm, 14 mm or 20 mm, thereby reducing the risk of breakage / tearing / damage of the tab 20 due to external collision, and improving the stiffness of the tab.

[0045] Furthermore, in this embodiment, the ratio of the length L2 of the pole lug 20 in the direction of the first side 11 to the length L1 of the pole piece body 10 is in the range of 10% to 20%; and / or, the ratio of the length of the orthographic projection of the first chamfer 101 on the first side 11 to the length L1 of the pole piece body 10 is in the range of 1% to 25%; and / or, the length of the orthographic projection of the second chamfer 201 in the direction of the third side 21 is 0.15 times to 3 times the length L3 of the third side 21 of the pole lug 20.

[0046] Specifically, in this embodiment, the ratio of the length L2 of the pole lug 20 in the direction of the first side 11 to the length L1 of the pole piece body 10 is preferably 14%~15%, thereby increasing the current flow capacity at the pole lug 20, so that the current flow capacity at the pole lug 20 meets the use of the battery under high current conditions, is beneficial to the heat dissipation of the battery, and improves the safety of the battery; or, the ratio of the length of the positive projection of the first chamfer 101 in the direction of the first side 11 to the length L1 of the pole piece body 10 is preferably 1%~2%, thereby better reducing the problem of the pole piece body 10 being bumped and causing corner bending, and material falling and dust generation during the stacking process; or, the length of the positive projection of any second chamfer 201 in the direction of the third side 21 is 0.18 times~0.2 times the length L3 of the third side 21 of the pole lug 20, thereby better reducing the risk of the pole lug 20 being damaged or bent by external collision, and improving the rigidity of the pole lug 20.

[0047] Furthermore, in one embodiment, please refer to FIG. 1 and FIG. 4 ; FIG. 4 is an enlarged view of point C in FIG. 1 .

[0048] In this embodiment, the fourth side 22 and the fifth side 23 both extend in a direction close to the pole piece body 10, and the fourth side 22 and the fifth side 23 are both connected to the first side 11 of the pole piece body 10; a first transition portion 401 is formed at the connection between the fourth side 22 and the first side 11, and a second transition portion 402 is formed at the connection between the fifth side 23 and the first side 11, and the first transition portion 401 and the second transition portion 402 both include a third chamfer 301.

[0049] Specifically, the third chamfer 301 is a rounded corner, and the angle range of the third chamfer 301 is greater than 90 degrees and less than 180 degrees; or, the angle range of the third chamfer 301 is greater than 90 degrees and less than 100 degrees; wherein, the angle of the third chamfer 301 is preferably one of 93 degrees, 94 degrees, 96 degrees, 98 degrees or 100 degrees, thereby reducing stress concentration and reducing the risk of fracture of the tab 20.

[0050] Furthermore, the third chamfer 301 includes a third arc segment 30A and at least one third transition segment 30B; in the first transition portion 401, the third arc segment 30A is connected to the fourth side 22 and / or the first side 11 through the third transition segment 30B; in the second transition portion 402, the third arc segment 30A is connected to the fifth side 23 and / or the first side 11 through the third transition segment 30B; wherein, the third arc segment 30A protrudes toward the direction close to the center of the pole piece body 10; wherein, in this embodiment, the third chamfer 301 includes a third arc segment 30A and at least one third transition segment 30B; Three arc segments 30A and the third transition segment 30B distributed at both ends of the third arc segment 30A, in the first transition portion 401, the third arc segment 30A is connected to the fourth side 22 and the first side 11 through the third transition segment 30B; in the second transition portion 402, the third arc segment 30A is connected to the fifth side 23 and the first side 11 through the third transition segment 30B; wherein, the third arc segment 30A protrudes toward the direction close to the center of the pole piece body 10; preferably, the third arc segment 30A is arranged tangent to the third transition segment 30B.

[0051] Specifically, in this embodiment, the third arc segment 30A is an arc segment with a single curvature, and the third transition segment 30B is a straight line segment; the curvature radius of the third arc segment 30A is greater than or equal to 0.1 mm and less than or equal to 25 mm; it can be understood that in this embodiment, a first transition portion 401 is formed at the connection between the fourth side 22 and the first side 11, and a second transition portion 402 is formed at the connection between the fifth side 23 and the first side 11, and the first transition portion 401 is formed at the connection between the fifth side 23 and the first side 11. 01 and the second transition portion 402 both include a third chamfer 301, the third chamfer 301 includes a third arc segment 30A and the third transition segment 30B distributed at both ends of the third arc segment 30A, wherein the third arc segment 30A is a circular arc segment with a single curvature, and the third transition segment 30B is a straight line segment. The circular arc segment structure can disperse the stress at the connection between the pole ear 20 and the pole piece body 10, optimize the stress condition of the pole ear 20, and reduce the risk of the pole ear 20 breaking.

[0052] At the same time, in this embodiment, by setting the third arc segment 30A and the third transition segment 30B to be tangent, the intersection of the side of the pole piece body 10 and the third chamfer 301, as well as the intersection of the side of the pole ear 20 and the third chamfer 301 are smoothly transitioned, which effectively prevents the battery from shaking due to external impact, thereby causing the risk of breakage at the connection between the pole ear 20 and the pole piece body 10.

[0053] Among them, the curvature radius of the third arc segment 30A is preferably one of 8 mm, 14 mm or 20 mm. It can be understood that this embodiment sets the curvature radius of the third arc segment 30A to be preferably one of 8 mm, 14 mm or 20 mm, thereby better reducing the stress concentration at the connection between the pole ear 20 and the pole piece body 10 and reducing the risk of breakage of the pole ear 20.

[0054] It should be noted that in the related art, due to the limitations of existing molds, the corners of the pole pieces are usually made into V-angles. In the embodiment of the present application, the arc segment of the first chamfer 101, the arc segment of the second chamfer 201 and the arc segment of the third chamfer 301 can all be made by laser cutting technology, so that the production of the pole piece is not restricted by existing molds, has high feasibility, low cost and is easy to produce.

[0055] In addition, in this embodiment, the first arc segment 10A, the second arc segment 20A and the third arc segment 30A are all circular arc segments with a single curvature, and the first transition segment 10B, the second transition segment 20B and the third transition segment 30B are all straight line segments for illustration only. This embodiment does not impose any specific restrictions on the shape of the first arc segment 10A, the shape of the second arc segment 20A, the shape of the third arc segment 30A, the shape of the first transition segment 10B, the shape of the second transition segment 20B and the shape of the third transition segment 30B.

[0056] Furthermore, in one embodiment, an active material layer 100 is provided on the electrode body 10, and a spacer 200A is provided between the edge of the active material layer 100 and the first side 11, and a ceramic coating 200 is coated in the spacer 200A, and the ceramic coating 200 at least covers a portion of the first chamfer 101; wherein, the material of the ceramic coating 200 includes but is not limited to boehmite.

[0057] It is understandable that, since burrs are prone to appear on the edge of the electrode body 10 during cutting during the battery production process, when burrs exist on the electrode body 10, the exposed burrs will pierce the diaphragm between the positive and negative electrode sheets of the battery, causing direct contact between the positive and negative electrode sheets of the battery, and causing an internal short circuit in the battery. In this embodiment, a spacer 200A is provided between the edge of the active material layer 100 and the first side 11, and the spacer 200A is coated with a ceramic coating 200, so that the surface of the electrode body 10 after cutting is smooth and burr-free, thereby avoiding the technical problem in the related art that burrs on the positive and negative electrode sheets of the battery affect the safety performance of the battery. The ceramic coating 200 can be applied before the edge of the electrode body 10 is cut, or the ceramic coating 200 can be applied after the edge of the electrode body 10 is cut, and this embodiment does not impose specific restrictions on this.

[0058] Furthermore, in one embodiment, please refer to Figures 1, 2 and 4, the ceramic coating 200 includes a first ceramic coating 210 and a second ceramic coating 220 connected to each other, the first ceramic coating 210 is coated on the spacer area 200A, and the second ceramic coating 220 is coated on the root surface of the pole ear 20 close to the pole piece body 10; it can be understood that this embodiment sets the second ceramic coating 220 to be coated on the root surface of the pole ear 20 close to the pole piece body 10, so that the surface of the side of the pole ear 20 close to the pole piece body 10 after cutting is smooth and burr-free, avoiding the technical problem in the related art that the burrs on the pole ear 20 affect the safety performance of the battery; at the same time, it can improve the strength of the pole piece and reduce the risk of bending and tearing at the root of the pole ear 20.

[0059] Specifically, in the direction in which the active material layer 100 points to the ceramic coating 200, the width h1 of the first ceramic coating 210 is greater than or equal to 1 mm and less than or equal to 3 mm, and the width h2 of the second ceramic coating 220 is greater than or equal to 4 mm and less than or equal to 6 mm; wherein, the width h1 of the first ceramic coating 210 is preferably one of 1 mm, 2 mm or 3 mm, and the width h2 of the second ceramic coating 220 is preferably one of 4 mm, 5 mm or 6 mm, so that the inside of the spacer 200A and the root surface of the pole ear 20 close to the pole piece body 10 are coated with a certain width of ceramic coating 200, so that the surface of the pole piece body 10 after cutting and the side surface of the pole ear 20 close to the pole piece body 10 are smooth and free of burrs, further avoiding the technical problem in the related art that the burrs in the pole piece body 10 and the pole ear 20 affect the safety performance of the battery.

[0060] Furthermore, in this embodiment, the first ceramic coating layer 210 is adjacent to an edge of the active material layer 100 ; or, an overlapping portion 201A is defined between the first ceramic coating layer 210 and the active material layer 100 .

[0061] Preferably, in this embodiment, an overlapping portion 201A is provided between the first ceramic coating 210 and the active material layer 100. In the direction from the active material layer 100 toward the ceramic coating 200, the width h3 of the overlapping portion 201A ranges from greater than 0 to less than or equal to 1 mm, with the width h3 of the overlapping portion 201A preferably being 1 mm. When the electrode is a positive electrode, the provision of the overlapping portion 201A allows the first ceramic coating 210 to cover the thinner edge of the active material layer 100, thereby reducing the width of the active material layer 100 of the positive electrode and preventing lithium deposition. Furthermore, a seamless state can be achieved between the ceramic coating 200 and the active material layer 100, thereby ensuring that the ceramic coating 200 covers at least a portion of the first chamfer 101. This further ensures that the surface of the electrode body 10 after cutting is smooth and burr-free, thus avoiding the technical problem of burrs on the electrode body 10 affecting battery safety.

[0062] In another embodiment, the first ceramic coating 210 is adjacent to the active material layer 100, reducing the total amount of lithium ions released at the edge of the positive electrode sheet, reducing the risk of lithium plating during high-rate charge and discharge of the lithium-ion battery, improving the safety performance of the lithium-ion battery, and enhancing the capacity retention rate of the lithium-ion battery in the later stage of the cycle.

[0063] In another embodiment, the thickness of the active material layer 100 gradually decreases at the edge close to the first ceramic coating 210 so as not to affect the overall thickness of the electrode piece; and / or, the thickness of the second ceramic coating 220 gradually decreases at the edge away from the first ceramic coating 210 to ensure the thickness of the electrode tab 20 and reduce the risk of burrs on the electrode tab 20 piercing the diaphragm and affecting the safety performance of the battery.

[0064] Example 2

[0065] Please refer to Figure 1 and Figure 5; Figure 5 is a second enlarged view of point A in Figure 1.

[0066] In this embodiment, the structure of the electrode is similar to / the same as that of the electrode provided in the above embodiment. For details, please refer to the description of the electrode in the above embodiment, which will not be repeated here. The only difference between the two is:

[0067] In this embodiment, the first transition section 10B, the second transition section 20B, and the third transition section 30B are all arc sections with a single curvature.

[0068] Specifically, in this embodiment, the first chamfer 101 is a curved segment composed of multiple arc segments connected end to end, and the first arc segment 10A and the first transition segment 10B are both arc segments with a single curvature; wherein the curvature radius of the first transition segment 10B is greater than the curvature radius of the first arc segment 10A.

[0069] It can be understood that, in this embodiment, the first chamfer 101 is arranged as a curved segment composed of multiple arc segments connected end to end, and the first arc segment 10A and the first transition segment 10B are both arc segments with a single curvature, which can effectively avoid the risk of folding between the two tangent points along the single outer arc structure and the edge of the pole piece 1 when the corners of the pole piece 1 are a single outer arc structure.

[0070] Furthermore, in this embodiment, the second chamfer 201 is a curved segment composed of multiple arc segments connected end to end, the second arc segment 20A and the second transition segment 20B are both arc segments with a single curvature, and the curvature radius of the second transition segment 20B is larger than the curvature radius of the second arc segment 20A; the third chamfer 301 is a curved segment composed of multiple arc segments connected end to end, the third arc segment 30A and the third transition segment 30B are both arc segments with a single curvature, and the curvature radius of the third transition segment 30B is larger than the curvature radius of the third arc segment 30A, and its beneficial effect is similar / same as the above-mentioned first chamfer 101 being a curved segment composed of multiple arc segments connected end to end, and this embodiment will not elaborate on this.

[0071] Example 3

[0072] Please refer to Figure 1 and Figure 6; Figure 6 is a third enlarged view of point A in Figure 1.

[0073] In this embodiment, the structure of the electrode 1 is similar to / identical to that of the electrode provided in the above embodiment. For details, please refer to the description of the electrode in the above embodiment, which will not be repeated here. The only difference between the two is:

[0074] In this embodiment, the first transition section 10B, the second transition section 20B, and the third transition section 30B are all spline curves with multiple curvature arc segments connected in sequence.

[0075] Specifically, in this embodiment, the first arc segment 10A is a circular arc segment with a single curvature, and the first transition segment 10B is a spline curve with multiple curvature arc segments connected in sequence; it can be understood that this embodiment sets the first chamfer 101 to include a spline curve-circular arc segment-spline curve connected end to end, so that during the production or use of the battery, when the battery is hit by an external force and shakes, the first chamfer 101 with the circular arc segment can prevent the electrode 1 from piercing the diaphragm, thereby avoiding the problem in the related art that the edge corners of the electrode 1 are acute angles, obtuse angles or right angles, and effectively preventing the battery from shaking due to an external force impact, which causes the edge corners of the electrode 1 to pierce the diaphragm.

[0076] Furthermore, in this embodiment, the second arc segment 20A is a circular arc segment with a single curvature, the second transition segment 20B is a spline curve composed of multiple curvature arc segments connected in sequence, the third arc segment 30A is a circular arc segment with a single curvature, and the third transition segment 30B is a spline curve composed of multiple curvature arc segments connected in sequence. The beneficial effects are similar / identical to those of the above-mentioned first chamfer 101 including the end-to-end connected spline curve-circular arc segment-spline curve, and this embodiment will not elaborate on this.

[0077] This embodiment further provides a battery cell, comprising a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet.

[0078] The positive electrode sheet includes a positive electrode sheet body and a positive electrode ear. The positive electrode sheet body is rectangular in shape, and the four corners of the positive electrode sheet body are provided with the first chamfer described in any of the above embodiments. The positive electrode ear includes the second chamfer described in any of the above embodiments, and the connection between the positive electrode sheet body and the positive electrode ear includes the third chamfer described in any of the above embodiments; the negative electrode sheet includes a negative electrode sheet body and a negative electrode ear. The negative electrode sheet body is rectangular in shape, and the four corners of the negative electrode sheet body are provided with the first chamfer 101 described in any of the above embodiments. The negative electrode ear includes the second chamfer described in any of the above embodiments, and the connection between the negative electrode sheet body and the negative electrode ear includes the third chamfer described in any of the above embodiments.

[0079] In which, an active material layer is provided on the positive electrode sheet body, and there is a spacing area between the edge of the active material layer and the first side of the positive electrode sheet body, and a ceramic coating is coated in the spacing area, and the ceramic coating at least covers a portion of the first chamfer of the positive electrode sheet body; the positive projection of the negative electrode sheet on the diaphragm covers the positive projection of the ceramic coating of the positive electrode on the diaphragm, so that the surface of the positive electrode sheet body after cutting is smooth and burr-free, avoiding the technical problem in the related art that burrs on the positive and negative electrode sheets of the battery affect the safety performance of the battery.

[0080] It should be noted that the first chamfer 101 , the second chamfer 201 , the third chamfer 301 and the ceramic coating 200 have been described in detail in the above embodiment and will not be repeated here.

[0081] This embodiment also provides a battery module, comprising a shell and the battery cell described in any of the above embodiments, the shell having a accommodating cavity, and the battery cell is located in the accommodating cavity; preferably, the shell is a soft-pack polymer shell or a square shell, the battery cell includes a lithium battery cell, and the battery module is used as a power supply for electrical equipment; wherein, the electrical equipment may be an automobile, an aircraft, mechanical production equipment, etc.

Claims

1. A pole piece, wherein: include: A pole piece body, the pole piece body comprising a first side edge and a second side edge connected to each other, a first chamfer being provided at a connection between the first side edge and the second side edge; The first chamfer includes a first arc segment and at least one first transition segment, the first arc segment is connected to the first side edge and / or the second side edge through the first transition segment, and the first arc segment protrudes in a direction away from the center of the pole piece body.

2. The pole piece according to claim 1, wherein: The pole piece body is polygonal, and each corner of the pole piece body is provided with the first chamfer.

3. The pole piece according to claim 1, wherein: The pole piece further includes a pole ear, which is located on the first side and extends in a direction away from the pole piece body, and the pole ear and the pole piece body are integrally formed by laser cutting.

4. The pole piece according to claim 3, wherein: The pole ear comprises a third side, a fourth side and a fifth side, the third side is away from the pole piece body, and the fourth side is arranged opposite to the fifth side; The fourth side and the fifth side are respectively connected to two ends of the third side, and second chamfers are formed at the connection positions.

5. The pole piece according to claim 4, wherein: The second chamfer includes a second arc segment and at least one second transition segment; At the intersection of the fourth side and the third side, the second arc segment is connected to the fourth side and / or the third side through the second transition segment; At the intersection of the fifth side and the third side, the second arc segment is connected to the fifth side and / or the third side through the second transition segment; Wherein, the second arc segment protrudes in a direction away from the center of the tab.

6. The pole piece according to claim 5, wherein: The fourth side edge and the fifth side edge both extend in a direction close to the pole piece body, and the fourth side edge and the fifth side edge are both connected to the first side edge of the pole piece body; A first transition portion is formed at a connection between the fourth side and the first side, and a second transition portion is formed at a connection between the fifth side and the first side. Both the first transition portion and the second transition portion include a third chamfer.

7. The pole piece according to claim 6, wherein: The third chamfer is a rounded angle, and the angle range of the third chamfer is greater than 90 degrees and less than 180 degrees; Alternatively, the angle range of the third chamfer is greater than 90 degrees and less than 100 degrees.

8. The pole piece according to claim 6, wherein: The third chamfer includes a third arc segment and at least one third transition segment; In the first transition portion, the third arc segment is connected to the fourth side and / or the first side through the third transition segment, and the third arc segment protrudes toward the center of the pole piece body; In the second transition portion, the third arc segment is connected to the fifth side and / or the first side through the third transition segment, and the third arc segment protrudes toward the center of the pole piece body.

9. The pole piece according to claim 8, wherein: The first arc segment, the second arc segment and the third arc segment are all circular arc segments with a single curvature; The radius of curvature of the first arc segment is greater than or equal to 0.1 mm and less than or equal to 30 mm; and / or, the radius of curvature of the second arc segment is greater than or equal to 0.1 mm and less than or equal to 25 mm; And / or, the radius of curvature of the third arc segment is greater than or equal to 0.1 mm and less than or equal to 25 mm.

10. The pole piece according to claim 8, wherein: The first transition section, the second transition section and the third transition section are all straight line sections; Or, the first transition section, the second transition section and the third transition section are all arc sections with a single curvature; Alternatively, the first transition segment, the second transition segment and the third transition segment are all spline curves with multiple curvature arc segments connected in sequence.

11. The pole piece according to claim 4, wherein: The ratio of the length of the pole ear to the length of the pole piece body in the first side direction is in the range of 10% to 20%; And / or, the ratio of the length of the orthographic projection of the first chamfer on the first side to the length of the pole piece body is in a range of 1% to 25%; And / or, the length of the orthographic projection of any one of the second chamfers in the direction of the third side edge is 0.15 to 3 times the length of the third side edge of the pole lug.

12. The pole piece according to any one of claims 3 to 11, wherein: An active material layer is provided on the pole piece body, and a spacing area is provided between the edge of the active material layer and the first side edge. A ceramic coating is coated in the spacing area, and the ceramic coating at least covers a portion of the first chamfer.

13. The pole piece according to claim 12, wherein: The material of the ceramic coating is boehmite.

14. The pole piece according to claim 12, wherein: The ceramic coating comprises a first ceramic coating and a second ceramic coating which are connected to each other. The first ceramic coating is coated on the spacer area, and the second ceramic coating is coated on the root surface of the pole ear close to the pole piece body.

15. The pole piece according to claim 14, wherein: In the direction from the active material layer to the ceramic coating, the width of the first ceramic coating is greater than or equal to 1 mm and less than or equal to 3 mm, and the width of the second ceramic coating is greater than or equal to 4 mm and less than or equal to 6 mm.

16. The pole piece according to claim 14, wherein: The first ceramic coating is adjacent to an edge of the active material layer; Alternatively, the first ceramic coating layer and the active material layer have an overlapping portion.

17. The pole piece according to claim 16, wherein: In the direction from the active material layer to the ceramic coating, the width of the overlapping portion is greater than 0 and less than or equal to 1 mm; and / or, the thickness of the active material layer gradually decreases near the edge of the first ceramic coating layer; And / or, the thickness of the second ceramic coating gradually decreases as the edge away from the first ceramic coating.

18. A battery cell, wherein: It comprises a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet comprises the electrode sheet according to any one of claims 1 to 17, and the negative electrode sheet comprises the electrode sheet according to any one of claims 1 to 11.

19. The battery cell according to claim 18, wherein: The orthographic projection of the negative electrode sheet on the diaphragm covers the orthographic projection of the ceramic coating of the positive electrode on the diaphragm.

20. A battery, wherein: The invention comprises a shell and a battery cell as claimed in any one of claims 18 to 19, wherein the shell has a receiving cavity, and the battery cell is located in the receiving cavity.

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