Pole piece, electrochemical device and electric equipment

Abstract

The invention discloses a pole piece, an electrochemical device and electric equipment, the pole piece comprises a base part and a pole lug, the base part comprises a first edge connected with the pole lug, and the pole lug comprises an extension part and a connection part. In the length direction of the pole piece, the extension part comprises a first side edge and a second side edge which are opposite, the connecting part comprises a third side edge and a fourth side edge which are opposite, a first connecting point is arranged between the third side edge and the first side edge, and a third connecting point is arranged between the third side edge and the first side edge; a second connecting point is arranged between the fourth side edge and the second side edge, and a fourth connecting point is arranged between the fourth side edge and the first edge. The extension line of the first side edge and the first edge have a first intersection point, the included angle between the ray from the first intersection point to the first connection point and the ray from the first intersection point to the fourth connection point is alpha 1, and alpha 1 is smaller than 90 degrees. A connecting line from the first connecting point to the third connecting point is used as a first reference line, and the connecting part comprises a first reinforcing area defined by the third side edge and the first reference line. According to the invention, the problems of bending and tearing of the tabs can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a pole piece, an electrochemical device, and an electrical equipment. Background Art

[0002] Because the battery has a multi-pole ear structure, the current can be led out through multiple pole ears, which greatly shortens the conduction path of electrons in the electrode. This can meet the high-rate application needs of electrical equipment such as mobile phones, laptops, drones, power tools, electric vehicles, and electric two-wheelers, and has therefore been widely used. Summary of the invention

[0003] However, the inventors of the present application have discovered that the existing pole pieces with multi-ear tab structures are prone to bending and inset of the ear tabs during the production and winding process, which seriously affects the production yield. In addition, for batteries with multi-ear tab structures, the risk of ear tab tearing during impacts such as falling also increases accordingly, affecting the normal use of electrical equipment.

[0004] In view of this, the present application provides a pole piece, an electrochemical device and an electrical equipment to improve the bending and insertion of the pole ear during the production process, improve the production efficiency of the electrochemical device, and reduce the risk of tearing at the root of the pole ear during the impact of falling or other impacts of the electrochemical device, thereby improving the reliability of the electrochemical device.

[0005] In the first aspect of the present application, a pole piece is provided, the pole piece comprising a base and a pole ear. Along the length direction of the pole piece, the base comprises a first side connected to the pole ear, and the pole ear comprises an extension portion and a connection portion. Along the length direction of the pole piece, the extension portion comprises a first side and a second side arranged oppositely. The connection portion is located between the base and the extension portion, and along the length direction of the pole piece, the connection portion comprises a third side and a fourth side arranged oppositely, the third side is connected to the first side and the first side, the fourth side is connected to the first side and the second side, there is a first connection point between the third side and the first side, there is a second connection point between the fourth side and the second side, there is a third connection point between the third side and the first side, and there is a fourth connection point between the fourth side and the first side. Observed along the thickness direction of the pole ear, the extension line of the first side has a first intersection with the first side, and the first intersection is located between the third connection point and the fourth connection point; the angle between the ray from the first intersection to the first connection point and the ray from the first intersection to the fourth connection point is α1, satisfying α1<90°. Observing along the thickness direction of the tab, with the line from the first connection point to the third connection point as the first reference line, the connection portion includes a first reinforcement area, and the first reinforcement area is surrounded by the third side and the first reference line.

[0006] By satisfying α1<90°, the first side of the pole ear is tilted, and a first reinforcement area is set between the third side and the first reference line. This is beneficial to improving the swing stiffness and torsional stiffness of the first side of the pole ear, thereby suppressing the bending and interpolation of the pole ear during the production and winding process, improving the production quality rate of the electrochemical device, and at the same time helping to reduce the risk of tearing at the root of the pole ear during the impact of falling or other impacts of the electrochemical device, thereby improving the reliability of the electrochemical device.

[0007] In some embodiments, the third side includes a fifth side and a sixth side, the fifth side is connected to the first side, the sixth side is connected to the first side, and the angle between the fifth side and the sixth side is δ1, satisfying 90°<δ1<180°. In this way, the first reinforcement area has an obtuse structure, which is conducive to improving the swing stiffness and torsional stiffness of the tab, thereby further suppressing the bending and interpolation of the tab during the production and winding process, improving the production rate of the electrochemical device, and at the same time, it is conducive to further reducing the risk of tearing of the root of the tab during the impact of the electrochemical device such as falling, and improving the reliability of the electrochemical device.

[0008] In some embodiments, 180°-α1<δ1 is satisfied. In this way, the obtuse angle of the outer contour of the first reinforcement area is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the tab.

[0009] In some embodiments, the third side includes a fifth side and a sixth side, a fifth connection point is provided between the fifth side and the sixth side, the fifth side is connected to the first side, the sixth side is connected to the first side, and the angle between the ray from the third connection point to the fifth connection point and the ray from the third connection point to the fourth connection point is β1, satisfying β1≤α1<90°, and / or 60°≤β1≤90°. In this way, it is beneficial to improve the rigidity of the tab connection, thereby better suppressing the swing and torsion of the tab, thereby improving the production rate of the electrochemical device, and reducing the risk of tearing of the tab root during the impact of the electrochemical device such as falling, thereby improving the reliability of the electrochemical device.

[0010] In some embodiments, along the width direction of the pole piece, the height of the pole ear is H, and the height of the connecting portion is h, satisfying h / H≥1 / 5.

[0011] In some embodiments, when viewed along the thickness direction of the tab, the extension line of the second side has a second intersection with the first side, and the second intersection is located between the third connection point and the fourth connection point; the angle between the ray from the second intersection to the second connection point and the ray from the second intersection to the third connection point is α2, and α2<90° is satisfied. When viewed along the thickness direction of the tab, the line connecting the second connection point to the fourth connection point is the second reference line; the connecting portion further includes a main body area and a second reinforcement area, the main body area is located between the first reference line and the second reference line, and the second reinforcement area is surrounded by the fourth side and the second reference line.

[0012] In the above embodiment, by satisfying α2<90°, the second side of the pole ear is inclined, and a second reinforcement area is set between the fourth side and the second reference line, which is beneficial to improving the swing stiffness and torsional stiffness of the second side of the pole ear, thereby further suppressing the bending and interpolation of the pole ear during the production and winding process, improving the production quality rate of the electrochemical device, and at the same time helping to reduce the risk of tearing at the root of the pole ear during the impact of the electrochemical device such as falling, thereby further improving the reliability of the electrochemical device.

[0013] In some embodiments, the fourth side includes a seventh side and an eighth side, a sixth connection point is provided between the seventh side and the eighth side, the seventh side is connected to the second side, the eighth side is connected to the first side, and the angle between the seventh side and the eighth side is δ2, satisfying 90°<δ2<180°. In this way, the second reinforcement area has an obtuse structure, which is conducive to improving the swing stiffness and torsional stiffness of the second side of the pole ear, thereby further suppressing the bending and interpolation of the pole ear during the production and winding process, improving the production rate of the electrochemical device, and at the same time, it is conducive to further reducing the risk of tearing of the pole ear root during the impact of the electrochemical device such as falling, and improving the reliability of the electrochemical device.

[0014] In some embodiments, the angle between the ray from the fourth connection point to the sixth connection point and the ray from the fourth connection point to the third connection point is β2, satisfying β2≤α2<90°, and / or 60°≤β2≤90°. In this way, it is beneficial to improve the rigidity of the tab connection, thereby better suppressing the swing and torsion of the tab, thereby improving the production rate of the electrochemical device, and reducing the risk of tearing of the tab root during the impact of the electrochemical device such as falling, thereby improving the reliability of the electrochemical device.

[0015] In some embodiments, the distance between the first intersection and the second intersection is L; the distance between the third connection point and the fourth connection point is L1, satisfying L1 ≥ 1.1 × L. This is conducive to improving the swing stiffness and torsional stiffness of the tab, thereby improving the production rate of the electrochemical device, and reducing the risk of tearing at the root of the tab during the impact of the electrochemical device such as falling, thereby improving the reliability of the electrochemical device.

[0016] In some embodiments, 180°-α2<δ2 is satisfied. In this way, the obtuse angle of the outer contour of the second reinforcement area is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the tab.

[0017] In some embodiments, the third side includes at least one of a fold line or an arc line.

[0018] In some embodiments, the fourth side includes at least one of a fold line or an arc line.

[0019] In some embodiments, the base includes a current collector and a first active material layer, and the first active material layer is disposed on a surface of the current collector.

[0020] In some embodiments, the electrode sheet is a negative electrode sheet, and the negative electrode sheet further includes a second active material layer, and the second active material layer is disposed on the surface of the connection portion. This is conducive to further improving the rigidity of the tab connection portion, thereby further inhibiting the bending and tearing of the tab.

[0021] In some embodiments, the electrode piece is a positive electrode piece, and the positive electrode piece further includes a first insulating layer, and the first insulating layer is disposed on the surface of the connection portion. In this way, the rigidity of the tab connection portion is further improved, thereby further suppressing the bending and tearing of the tab.

[0022] In a second aspect of the present application, an electrochemical device is provided, the electrochemical device comprising a wound electrode assembly, the electrode assembly comprising a pole piece as in any of the above embodiments. The swing stiffness and torsional stiffness of the pole ear in the pole piece are improved, which is conducive to reducing the risk of tearing of the pole ear root during the impact process such as falling of the electrochemical device, thereby improving the reliability of the electrochemical device.

[0023] In a third aspect of the present application, an electrical device is provided, wherein the electrical device comprises the electrochemical device in the above-mentioned embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of an electrical device provided in one embodiment of the present application.

[0025] Figure 2 A schematic diagram of an electrode assembly provided in accordance with an embodiment of the present application.

[0026] Figure 3 This is a front view of the pole piece in the unfolded state provided by one embodiment of the present application.

[0027] Figure 4 A side view of a pole piece in an expanded state provided in one embodiment of the present application.

[0028] Figure 5 A schematic diagram of a base and a tab provided in accordance with an embodiment of the present application.

[0029] Figure 6 A partial view of a first reinforcement area of ​​a connection portion provided for an embodiment of the present application.

[0030] Figure 7 A partial view of the second reinforcement area of ​​the connecting portion provided for an embodiment of the present application.

[0031] Figure 8 It is a schematic diagram of a base and a trapezoidal pole ear in the related art.

[0032] Fig. 9 A schematic diagram of a base and a tab provided in accordance with another embodiment of the present application.

[0033] Fig.10 A schematic diagram of a base and a tab provided in yet another embodiment of the present application.

[0034] Fig.11 A schematic diagram of a base and a tab provided in yet another embodiment of the present application.

[0035] Fig.12 A schematic diagram of a base and a tab provided in yet another embodiment of the present application.

[0036] Main component symbols

[0037] Pole piece 10 Current collector 10a First active material layer 10 b Second active material layer 10c First insulating layer 10d The second insulating layer 10e Base 11 First side 111 The first intersection point 111a The second intersection point 111b Tab 12 Extension 121 First side 1211 Second side 1212 First reference line 121a Second reference line 121b Connecting part 122 The third side 1221 Fourth side 1222 Fifth side 1223 Sixth side 1224 Seventh side 1225 Eighth side 1226 First reinforcement area 122a Second reinforcement area 122b First connection point 12a Second connection point 12b The third connection point 12c Fourth connection point 12d Fifth connection point 12e Sixth connection point 12f Positive electrode tab 1201 Negative electrode tab 1202 Electrode assembly 101 Electrochemical device 100 Equipment body 200 Electrical equipment 1000 Trapezoidal tab 12' The length direction of the pole piece X

[0038] Width direction Y of the pole piece

[0039] The thickness direction of the tab Z DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0041] It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "located on" another component, it may be directly located on the other component or there may be a central component at the same time. The terms "top", "bottom", "upper", "lower", "left", "right", "front", "back", and similar expressions used herein are for illustrative purposes only.

[0042] The terms "first", "second", etc. are only used to distinguish different objects and shall not be understood as indicating or implying relative importance or implying the quantity, specific order or primary and secondary relationship of the technical features indicated.

[0043] The term "parallel" is used to describe the ideal state between two parts. In actual production or use, two parts may be approximately parallel. The two parts described as "parallel" may not be absolutely straight lines or planes, but may be roughly straight lines or planes. From a macroscopic point of view, if the overall extension direction is a straight line or a plane, the parts can be considered "straight" or "plane".

[0044] It should be recognized that the sizes and thicknesses of the components shown in the drawings are for better understanding and more convenient description, and the present application is not limited to the sizes and thicknesses shown in the drawings.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0046] Some embodiments of the present application will be described below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0047] See also Figure 1 Some embodiments of the present application provide an electrical device 1000 , and the electrical device 1000 includes an electrochemical device 100 .

[0048] In some embodiments, see Figure 1 The electrical equipment 1000 further includes an equipment body 200 , and the electrochemical device 100 is installed in the equipment body 200 .

[0049] In some embodiments, the electrical device 1000 may be a mobile phone, a laptop computer, a tablet computer, a drone, an electric tool, an electric toy, a game console, a video recorder, a portable recorder, a radio, a smart watch, an electric car or an electric two-wheeled vehicle, etc., which are not listed one by one here.

[0050] In some embodiments, see Figure 2 The electrochemical device 100 includes an electrode assembly 101 , and the electrode assembly 101 includes a pole piece 10 , and the pole piece 10 includes a positive pole piece and a negative pole piece.

[0051] In some embodiments, the electrode assembly 101 further includes a diaphragm (not shown), which is disposed between the positive electrode sheet and the negative electrode sheet and is used to isolate the positive electrode sheet from the negative electrode sheet.

[0052] In some embodiments, the diaphragm can be made of materials such as polyethylene (PE) or polypropylene (PP).

[0053] The electrode assembly 101 may be a winding structure or a stacked structure. When the electrode assembly 101 is a winding structure, the positive electrode sheet may include multiple positive electrode tabs 1201, and the negative electrode sheet may include multiple negative electrode tabs 1202. After winding, when observed along the thickness direction of the electrode assembly 101, the multiple positive electrode tabs 1201 may overlap with each other, and the multiple negative electrode tabs 1202 may also overlap with each other; when the electrode assembly 101 is a stacked structure, the electrode assembly 101 includes multiple positive electrode sheets and multiple negative electrode sheets, each positive electrode sheet includes at least one positive electrode tab 1201, and each negative electrode sheet includes at least one negative electrode tab 1202. When observed along the thickness direction of the electrode assembly 101, the positive electrode tabs 1201 of the multiple positive electrode sheets may overlap with each other, and the negative electrode tabs 1202 of the multiple negative electrode sheets may also overlap with each other.

[0054] In some embodiments, see Figure 3 and Figure 4 The electrode sheet 10 includes a base 11, the base 11 includes a current collector 10a and a first active material layer 10b, the first active material layer 10b is arranged on the surface of the current collector 10a, the electrode sheet 10 can be a positive electrode sheet or a negative electrode sheet, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, the positive electrode current collector can be a metal layer including at least one of aluminum, nickel, tantalum, titanium, etc., such as aluminum foil; the positive electrode active material layer includes a positive electrode active material, the positive electrode active material can include at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate or lithium manganese oxide, etc. The negative electrode sheet 10 includes a negative electrode current collector and a negative electrode active material layer, the negative electrode current collector can be a metal layer including at least one of copper, nickel, tantalum, titanium, etc., such as copper foil; the negative electrode active material layer includes a negative electrode active material, the negative electrode active material can include at least one of graphite, hard carbon, soft carbon, silicon, silicon oxygen material, silicon carbon material, etc.

[0055] In some embodiments, see Figures 3 to 5 The pole piece 10 includes a base portion 11 and a pole ear 12 connected to each other. The pole ear 12 includes an extension portion 121 and a connection portion 122 . The connection portion 122 is located between the extension portion 121 and the base portion 11 , and the connection portion 122 connects the extension portion 121 and the base portion 11 .

[0056] It should be noted that the connection portion 122 is connected to the current collector 10 a in the base 11 , and the tab 12 can be cut and formed integrally with the current collector 10 a . Along the width direction Y of the pole piece 10 , the tab 12 is located at one side of the base 11 .

[0057] In some embodiments, see Figures 5 to 7, along the length direction X of the pole piece 10, the base portion 11 includes a first side 111 connected to the pole ear 12. Along the length direction X of the pole piece 10, the extension portion 121 includes a first side 1211 and a second side 1212 arranged opposite to each other, and the connection portion 122 includes a third side 1221 and a fourth side 1222 arranged opposite to each other. The third side 1221 is connected to the first side 111 and the first side 1211, and the fourth side 1222 is connected to the first side 111 and the second side 1212. There is a first connection point 12a between the third side 1221 and the first side 1211, a second connection point 12b between the fourth side 1222 and the second side 1212, a third connection point 12c between the third side 1221 and the first side 111, and a fourth connection point 12d between the fourth side 1222 and the first side 111. Observing along the thickness direction Z of the pole lug 12, the extension line of the first side 1211 and the first side 111 have a first intersection 111a, and the first intersection 111a is located between the third connection point 12c and the fourth connection point 12d. The angle between the ray from the first intersection 111a to the first connection point 12a and the ray from the first intersection 111a to the fourth connection point 12d is α1, satisfying α1<90°. Observing along the thickness direction Z of the pole lug 12, with the line from the first connection point 12a to the third connection point 12c as the first reference line 121a, the connecting portion 122 includes a first reinforcement area 122a, and the first reinforcement area 122a is surrounded by the third side 1221 and the first reference line 121a.

[0058] The inventors of the present application have discovered that the pole ear 12 is easily subjected to force and may swing or twist during the production processes such as cutting and forming and winding of the pole piece 10. When swinging or twisting, the pole ear 12 is prone to bending, intercalation (causing contact with the pole piece 10 of a different polarity), etc., seriously affecting the production yield. In addition, the risk of the pole ear 12 tearing in the electrochemical device 100 having a multi-pole ear 12 structure during impact such as falling also increases accordingly, affecting the normal use of the electrical equipment 1000. The present application satisfies α1<90°, so that the first side 1211 of the pole lug 12 is tilted, and a first reinforcement area 122a is set between the third side 1221 and the first reference line 121a, which is beneficial to improving the swing stiffness and torsional stiffness of the first side of the pole lug 12, thereby suppressing the bending and intercalation of the pole lug 12 during the production and winding process, improving the production quality rate of the electrochemical device 100, and at the same time helping to reduce the risk of tearing at the root of the pole lug 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0059] It can be understood that the first intersection 111a between the extension line of the first side 1211 and the first side 111 can be understood as the intersection of the extension line of the first side 1211 and the straight line where the first side 111 is located. The first side is the side where the first side 1211 is provided on the tab 12. In some embodiments, α1≤85°. Exemplarily, α1 can be any angle of 85°, 80°, 70°, 60°, 50°, 45°, or a range formed by any two of them.

[0060] In some embodiments, see Figures 5 to 7 Along the width direction Y of the pole piece 10, the projection of the extension portion 121 is located within the projection of the connecting portion 122, which is beneficial for making the size of the connecting portion 122 in the length direction X of the pole piece 10 larger than the size of the extension portion 121 in the length direction X of the pole piece 10, thereby facilitating the improvement of the rigidity of the pole lug 12 and reducing the possibility of bending and tearing of the pole lug 12.

[0061] In some embodiments, see Figures 5 to 7 , observed along the thickness direction Z of the pole ear 12, the extension line of the second side 1212 and the first side 111 have a second intersection 111b, and the second intersection 111b is located between the third connection point 12c and the fourth connection point 12d. The angle between the ray from the second intersection 111b to the second connection point 12b and the ray from the second intersection 111b to the third connection point 12c is α2, satisfying α2<90°. Observed along the thickness direction Z of the pole ear 12, the line connecting the second connection point 12b to the fourth connection point 12d is the second reference line 121b. The connecting portion 122 also includes a main body area and a second reinforcement area 122b, the main body area is located between the first reference line 121a and the second reference line 121b, and the second reinforcement area 122b is surrounded by the fourth side 1222 and the second reference line 121b. By satisfying α2<90°, the second side 1212 of the pole lug 12 is tilted, and a second reinforcement area 122b is set between the fourth side 1222 and the second reference line 121b, which is beneficial to improving the swing stiffness and torsional stiffness of the second side of the pole lug 12, thereby further suppressing the bending and intercalation of the pole lug 12 during the production and winding process, improving the production quality rate of the electrochemical device 100, and at the same time helping to reduce the risk of tearing at the root of the pole lug 12 during the impact of the electrochemical device 100 such as falling, thereby further improving the reliability of the electrochemical device 100.

[0062] It can be understood that the second intersection 111b between the extension line of the second side 1212 and the first side 111 can be understood as the intersection of the extension line of the second side 1212 and the straight line where the first side 111 is located. The second side is the side where the pole ear 12 is provided with the second side 1212. In some embodiments, α2≤85°. Exemplarily, α2 can be any angle of 85°, 80°, 70°, 60°, 50°, 45°, or a range formed by any two of them.

[0063] In some embodiments, the first side 1211 and the second side 1212 may be in a straight line or in an arc shape. When the first side 1211 and the second side 1212 are in a straight line, the extension line of the first side 1211 and the second side 1212 is a straight line. When the first side 1211 and the second side 1212 are in an arc shape, the extension line of the first side 1211 and the second side 1212 is a tangent line of the first side 1211 at the first intersection 111a and a tangent line of the second side 1212 at the second intersection 111b.

[0064] In some embodiments, see Figures 5 to 7 The third side 1221 includes a fifth side 1223 and a sixth side 1224 connected to each other, the fifth side 1223 is connected to the first side 1211, and the sixth side 1224 is connected to the first side 111. The angle between the fifth side 1223 and the sixth side 1224 is δ1, which satisfies 90°<δ1<180°. When this condition is met, the outer contour of the first reinforcement area 122a has an obtuse structure, which is conducive to improving the swing stiffness and torsional stiffness of the tab 12, thereby further suppressing the bending and interpolation of the tab 12 during the production and winding process, improving the production rate of the electrochemical device 100, and at the same time, it is conducive to further reducing the risk of tearing of the root of the tab 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0065] Exemplarily, δ1 may be any angle of 100°, 110°, 120°, 130°, 140°, 150°, or a range formed by any two of them.

[0066] In some embodiments, see Figures 5 to 7 , satisfying 180°-α1<δ1. When this condition is met, the obtuse angle of the outer contour of the first reinforcement area 122a is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the tab 12, and further beneficial to suppress the bending and tearing of the tab 12.

[0067] In some embodiments, see Figures 5 to 7, the third side 1221 includes a fifth side 1223 and a sixth side 1224 connected to each other, a fifth connection point 12e is provided between the fifth side 1223 and the sixth side 1224, the fifth side 1223 is connected to the first side 1211, the sixth side 1224 is connected to the first side 111, and the angle between the ray from the third connection point 12c to the fifth connection point 12e and the ray from the third connection point 12c to the fourth connection point 12d is β1, satisfying β1≤α1<90°, and / or 60°≤β1≤90°. When this condition is met, it is beneficial to improve the rigidity of the connection portion 122 of the tab 12, thereby better suppressing the swing and torsion of the tab 12, thereby improving the production rate of the electrochemical device 100, and reducing the risk of tearing of the root of the tab 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0068] Exemplarily, β1 may be any angle of 60°, 70°, 80°, 85°, 90°, or a range formed by any two of them.

[0069] In some embodiments, see Figures 5 to 7 , the fourth side 1222 includes a seventh side 1225 and an eighth side 1226, a sixth connection point 12f is provided between the seventh side 1225 and the eighth side 1226, the seventh side 1225 is connected to the second side 1212, the eighth side 1226 is connected to the first side 111, and the angle between the seventh side 1225 and the eighth side 1226 is δ2, satisfying 90°<δ2<180°. When this condition is met, the outer contour of the second reinforcement area 122b has an obtuse structure, which is conducive to improving the swing stiffness and torsional stiffness of the tab 12, thereby further suppressing the bending and interpolation of the tab 12 during the production and winding process, improving the production rate of the electrochemical device 100, and at the same time, further reducing the risk of tearing of the root of the tab 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0070] Exemplarily, δ2 may be any angle of 100°, 110°, 120°, 130°, 140°, 150°, or a range formed by any two of them.

[0071] In some embodiments, see Figures 5 to 7, the angle between the ray from the fourth connection point 12d to the sixth connection point 12f and the ray from the fourth connection point 12d to the third connection point 12c is β2, satisfying β2≤α2<90°, and / or 60°≤β2≤90°. When this condition is met, it is beneficial to improve the rigidity of the connection portion 122 of the tab 12, thereby better suppressing the swing and torsion of the tab 12, thereby improving the production rate of the electrochemical device 100, and reducing the risk of tearing at the root of the tab 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0072] Exemplarily, β2 may be any angle of 60°, 70°, 80°, 85°, 90°, or a range formed by any two of them.

[0073] In some embodiments, see Figures 5 to 7 , satisfying 180°-α2<δ2. When this condition is met, the obtuse angle of the outer contour of the second reinforcement area 122 b is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the tab 12 , thereby helping to suppress the bending and tearing of the tab 12 .

[0074] In some embodiments, see Figures 5 to 7 , the distance between the first intersection 111a and the second intersection 111b is L; the distance between the third connection point 12c and the fourth connection point 12d is L1, satisfying L1≥1.1×L. When this condition is met, it is beneficial to improve the rigidity of the connection portion 122 of the tab 12, suppress the swing and torsion of the tab, thereby improving the production rate of the electrochemical device 100, and reducing the risk of tearing of the root of the tab 12 during the impact of the electrochemical device 100 such as falling, thereby improving the reliability of the electrochemical device 100.

[0075] Illustratively, L1 may be any one of 1.1L, 1.2L, 1.3L, 1.4L, and 1.5L, or may be a range formed by any two of them.

[0076] In some embodiments, see Figure 5 and Fig. 9, the third side 1221 includes a fold line, and the fold line can be a double fold line or a triple fold line. As an illustrative example, the third side 1221 includes a fifth side 1223 and a sixth side 1224 connected to each other, the fifth side 1223 is connected to the first side 1211, and the sixth side 1224 is connected to the first side 111. There is an angle δ1 between the fifth side 1223 and the sixth side 1224, so that the fifth side 1223 and the sixth side 1224 form a double fold line structure. The structure of the triple fold line of the third side 1221 will not be repeated here. Both the double fold line structure and the triple fold line structure of the third side 1221 are conducive to improving the swing stiffness and torsional stiffness of the pole lug 12, thereby helping to suppress the bending and tearing of the pole lug 12.

[0077] In some embodiments, see Fig.10 The third side 1221 includes an arc, that is, the outer contour of the third side 1221 is in an arc shape. The arc structure is beneficial to improving the swing stiffness and torsional stiffness of the tab 12, thereby helping to suppress the bending and tearing of the tab 12.

[0078] In some embodiments, see Figure 5 and Fig. 9 , the fourth side 1222 includes a fold line which may be a double fold line or a triple fold line. As an illustrative example, the fourth side 1222 includes a seventh side 1225 and an eighth side 1226, and there is a sixth connection point 12f between the seventh side 1225 and the eighth side 1226, the seventh side 1225 is connected to the second side 1212, the eighth side 1226 is connected to the first side 111, and there is an angle δ2 between the seventh side 1225 and the eighth side 1226, so that the seventh side 1225 and the eighth side 1226 form a double fold line structure. The structure of the triple fold line of the fourth side 1222 will not be repeated here. Both the double fold line structure and the triple fold line structure of the fourth side 1222 are conducive to improving the swing stiffness and torsional stiffness of the pole lug 12, thereby helping to suppress the bending and tearing of the pole lug 12.

[0079] In some embodiments, see Fig.10 The fourth side 1222 includes an arc, that is, the outer contour of the fourth side 1222 is in an arc shape. The arc structure is beneficial to improving the swing stiffness and torsional stiffness of the tab 12, thereby helping to suppress the bending and tearing of the tab 12.

[0080] In some embodiments, see Figure 3 and Fig.11The pole piece 10 further includes a second active material layer 10c, which is disposed on the surface of the connecting portion 122. The second active material layer 10c is disposed on the surface of the connecting portion 122, which is beneficial for the second active material layer 10c to share the stress transmitted to the pole tab 12, improve the rigidity of the connecting portion 122 of the pole tab 12, and further inhibit the bending and tearing of the pole tab 12.

[0081] It is understandable that the second active material layer 10c may be disposed on a partial surface of the connecting portion 122, such as the surface of the first region of the connecting portion 122 adjacent to the base 11, or may be disposed on the entire surface of the connecting portion 122, which is not specifically limited herein.

[0082] In some embodiments, the electrode 10 is a negative electrode. In this case, the first active material layer 10b and the second active material layer 10c are both negative active material layers, and their specific compositions are the same as those of the negative active material layers described above, which will not be described in detail here.

[0083] In some embodiments, see Fig.12 , the pole piece 10 further includes a first insulating layer 10d, which is disposed on the surface of the connecting portion 122. The first insulating layer 10d is disposed on the surface of the connecting portion 122, which is conducive to allowing the first insulating layer 10d to share the stress transmitted to the pole tab 12, improve the rigidity of the connecting portion 122 of the pole tab 12, and further inhibit the bending and tearing of the pole tab 12. It can be understood that the first insulating layer 10d can be disposed on a part of the surface of the connecting portion 122, such as the surface of the second region of the connecting portion 122 adjacent to the base 11, or can be disposed on the entire surface of the connecting portion 122, which is not specifically limited here.

[0084] In some embodiments, the electrode sheet 10 is a positive electrode sheet, the side of the current collector 10a adjacent to the electrode tab 12 includes a third region, and the electrode sheet 10 further includes a second insulating layer 10e, which is disposed on the surface of the third region. It can be understood that the second insulating layer 10e can be connected to the first insulating layer 10d.

[0085] In some embodiments, the first insulating layer 10d and the second insulating layer 10e may include inorganic particles and a binder. The first insulating layer 10d and the second insulating layer 10e may have the same or different compositions, which are not specifically limited herein.

[0086] It should be noted that chamfers or rounded corners may be present at the intersections and connection points on the outer contour of the pole piece 10 of the present application, and no specific limitation is made here.

[0087] In order to verify the effect of the pole piece 10 structure of the present application on improving the bending of the pole tab 12, a large soft-pack battery with multiple pole tabs 12 is used as an example to compare the production rate improvement effect, wherein each set of data uses 400 electrode assemblies 101, each electrode assembly 101 has 98 die-cut pole tabs 12, and the number of electrode assemblies 101 with the pole tab 12 folded during the winding process is counted. Figure 8 As shown, it has a trapezoidal tab 12', the bottom width L of the trapezoidal tab 12' is 45 mm, the slope foot α is 80°, and the height H of the tab is 24 mm; the tab 12 of the embodiment is further provided with a reinforcement area on the basis of the comparative example, and α1=α2=α=80° in the tab 12, and the bottom width L1, angle δ1 / δ2, angle β1 / β2 and height h of the connecting portion 122 of the tab 12 are adjusted. The test results are shown in Table 1 below:

[0088] Table 1: Comparative test data of the electrode tab 12 of the present application and the trapezoidal electrode tab 12'.

[0089]

[0090]

[0091] From the comparison between the embodiment and the comparative example in Table 1, it can be seen that by adopting the pole piece 10 structure of the embodiment of the present application, the proportion of the pole ear 12 of the electrode assembly 101 being folded can be significantly reduced, thereby improving the production efficiency of the electrochemical device 100. At the same time, since the swing stiffness and torsional stiffness of the pole ear 12 are improved, the risk of tearing at the root of the pole ear 12 during the impact of falling of the electrochemical device 100 can be reduced, thereby improving the reliability of the electrochemical device 100.

[0092] From the comparison between Example 1-2 and Examples 2-1 to 2-3, it can be seen that when β1≤α1<90° / β2≤α2<90° is further satisfied, it is beneficial to further improve the stiffness of the connecting portion 122 of the tab 12, thereby better suppressing the swinging and twisting of the tab 12, and further improving the production rate of the electrochemical device 100. At the same time, it can further reduce the risk of tearing at the root of the tab 12 during the impact of falling or other impacts of the electrochemical device 100, thereby improving the reliability of the electrochemical device 100.

[0093] In addition, those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not used to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A pole piece, comprising a base and a pole ear, wherein along the length direction of the pole piece, the base comprises a first edge connected to the pole ear, characterized in that: The tab comprises: An extension portion, along the length direction of the pole piece, the extension portion comprising a first side edge and a second side edge that are oppositely disposed; A connecting portion, the connecting portion is located between the base portion and the extending portion, and along the length direction of the pole piece, the connecting portion includes a third side and a fourth side that are arranged opposite to each other, the third side is connected to the first side and the first side, the fourth side is connected to the first side and the second side, a first connecting point is provided between the third side and the first side, a second connecting point is provided between the fourth side and the second side, a third connecting point is provided between the third side and the first side, and a fourth connecting point is provided between the fourth side and the first side; When viewed along the thickness direction of the tab, an extension line of the first side has a first intersection with the first side, and the first intersection is located between the third connection point and the fourth connection point; an angle between a ray from the first intersection to the first connection point and a ray from the first intersection to the fourth connection point is α1, satisfying α1<90°; Observing along the thickness direction of the tab, with a line from the first connection point to the third connection point as a first reference line, the connection portion includes a first reinforcement area, and the first reinforcement area is surrounded by the third side and the first reference line.

2. The pole piece according to claim 1, characterized in that: The third side includes a fifth side and a sixth side, the fifth side is connected to the first side, the sixth side is connected to the first side, and the angle between the fifth side and the sixth side is δ1, satisfying 90°<δ1<180°.

3. The pole piece according to claim 2, characterized in that: Satisfies 180°-α1<δ1.

4. The pole piece according to claim 1, characterized in that: At least one of the following conditions is met: (1) The third side includes a fifth side and a sixth side, a fifth connection point is provided between the fifth side and the sixth side, the fifth side is connected to the first side, the sixth side is connected to the first side, and the angle between the ray from the third connection point to the fifth connection point and the ray from the third connection point to the fourth connection point is β1, satisfying β1≤α1<90°, and / or 60°≤β1≤90°; (2) Along the width direction of the pole piece, the height of the pole ear is H, and the height of the connecting portion is h, satisfying h / H ≥ 1 / 5.

5. The pole piece according to claim 1, characterized in that: When viewed along the thickness direction of the tab, an extension line of the second side has a second intersection with the first side, and the second intersection is located between the third connection point and the fourth connection point; an angle between a ray from the second intersection to the second connection point and a ray from the second intersection to the third connection point is α2, satisfying α2<90°; Observing along the thickness direction of the tab, the line connecting the second connection point to the fourth connection point is taken as the second reference line; the connecting portion also includes a main body area and a second reinforcement area, the main body area is located between the first reference line and the second reference line, and the second reinforcement area is surrounded by the fourth side and the second reference line.

6. The pole piece according to claim 5, characterized in that: The fourth side includes a seventh side and an eighth side, a sixth connection point is provided between the seventh side and the eighth side, the seventh side is connected to the second side, and the eighth side is connected to the first side, and at least one of the following conditions is satisfied: (1) The angle between the seventh side and the eighth side is δ2, which satisfies 90°<δ2<180°; (2) The angle between the ray from the fourth connection point to the sixth connection point and the ray from the fourth connection point to the third connection point is β2, satisfying β2≤α2<90°, and / or 60°≤β2≤90°; (3) The distance between the first intersection point and the second intersection point is L; the distance between the third connection point and the fourth connection point is L1, satisfying L1≥1.1×L.

7. The pole piece according to claim 6, characterized in that: Satisfies 180°-α2<δ2.

8. The pole piece according to claim 1, characterized in that: At least one of the following conditions is met: (1) The third side includes at least one of a fold line or an arc line; (2) the fourth side includes at least one of a fold line or an arc line; (3) The base includes a current collector and a first active material layer, wherein the first active material layer is disposed on the surface of the current collector; (4) The electrode sheet is a negative electrode sheet, and the negative electrode sheet also includes a second active material layer, and the second active material layer is arranged on the surface of the connecting portion, or the electrode sheet is a positive electrode sheet, and the positive electrode sheet also includes a first insulating layer, and the first insulating layer is arranged on the surface of the connecting portion.

9. An electrochemical device, characterized in that: It comprises a wound electrode assembly, wherein the electrode assembly comprises a pole piece as described in any one of claims 1 to 8.

10. An electrical device, characterized in that: Comprising the electrochemical device as claimed in claim 9.

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