Pole piece, electrochemical device, and electric equipment

Abstract

The application discloses a pole piece, an electrochemical device and an electric equipment. The pole piece comprises a base and a tab. The base comprises a first side connected with the tab. The tab comprises an extension part and a connecting part. In the length direction of the pole piece, the extension part comprises opposite first and second side edges. The connecting part comprises opposite third and fourth side edges. The third side edge has a first connecting point between the first side edge and a third connecting point between the first side. The fourth side edge has a second connecting point between the second side edge and a fourth connecting point between the first side. The extension of the first side edge has a first intersection point with the first side. The angle between the ray from the first intersection point to the first connecting point and the ray from the first intersection point to the fourth connecting point is alpha 1, which satisfies alpha 1 < 90 DEG. The connecting part comprises a first reinforcing area surrounded by the third side edge and a first reference line. The first reference line is the line from the first connecting point to the third connecting point. The application is beneficial to improve the bending and tearing problems of the tab.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an electrode, an electrochemical device, and an electrical device. Background Technology

[0002] Because of its multi-tab structure, the current can be drawn out through multiple tabs, which greatly shortens the conduction path of electrons in the electrode. This enables the battery to meet the high-rate application requirements of electrical devices such as mobile phones, laptops, drones, power tools, electric vehicles, and electric two-wheelers, and thus it has been widely used. Summary of the Invention

[0003] However, the inventors of this application have found that existing multi-tab structure electrodes are prone to tab bending and indentation during the production and winding process, which seriously affects the production yield. In addition, batteries with multi-tab structure are at increased risk of tab tearing during impacts such as drops, which affects the normal use of electrical equipment.

[0004] In view of this, this application provides an electrode, an electrochemical device, and an electrical device to improve the bending and insertion phenomena of the electrode tab during the production process, increase the production yield of the electrochemical device, reduce the risk of tearing at the root of the electrode tab during impacts such as drops, and improve the reliability of the electrochemical device.

[0005] In a first aspect, this application provides an electrode sheet, which includes a base and a tab. Along the length of the electrode sheet, the base includes a first side connected to the tab, and the tab includes an extension and a connecting portion. Along the length of the electrode sheet, the extension includes a first side and a second side disposed opposite to each other. The connecting portion is located between the base and the extension. Along the length of the electrode sheet, the connecting portion includes a third side and a fourth side disposed opposite to each other. The third side connects to the first side and the first side, and the fourth side connects to the first side and the second side. A first connection point is formed between the third side and the first side, a second connection point is formed between the fourth side and the second side, a third connection point is formed between the third side and the first side, and a fourth connection point is formed between the fourth side and the first side. Viewed along the thickness direction of the tab, the extension line of the first side intersects the first side at a first point, which is located between the third and fourth connection points. The 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 α1, satisfying α1 < 90°. Viewed along the thickness direction of the tab, with the line connecting the first connection point to the third connection point as the first reference line, the connection part includes a first reinforcing area, which is formed by the third side and the first reference line.

[0006] By satisfying α1 < 90°, the first side of the electrode is tilted, and a first reinforcing zone is set between the third side and the first reference line. This helps to improve the swing stiffness and torsional stiffness of the first side of the electrode, thereby suppressing bending and insertion phenomena of the electrode during the production winding process, improving the production yield of the electrochemical device, and reducing the risk of tearing at the root of the electrode during impacts such as drops, thus 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 being connected to the first side and the sixth side being connected to the first side, with an included angle δ1 between the fifth and sixth sides, satisfying 90° < δ1 < 180°. Thus, the first reinforcing region has an obtuse angle structure, which is beneficial for improving the swing stiffness and torsional stiffness of the tab, thereby further suppressing bending and indentation phenomena of the tab during the production winding process, improving the production yield of the electrochemical device, and further reducing the risk of tearing at the root of the tab during impacts such as drops, thus improving the reliability of the electrochemical device.

[0008] In some embodiments, 180° - α1 < δ1 is satisfied. This increases the angle of the obtuse angle of the outer contour of the first reinforcing region, which is beneficial to further improve the swing stiffness and torsional stiffness of the electrode lug.

[0009] In some embodiments, the third side includes a fifth side and a sixth side, with a fifth connection point between the fifth and sixth sides. The fifth side is connected to the first side, and the sixth side is connected to the first side. 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°. This improves the stiffness of the tab connection, thereby better suppressing the swing and torsion of the tab, improving the production yield of the electrochemical device, and reducing the risk of tearing at the root of the tab during impacts such as drops, thus enhancing the reliability of the electrochemical device.

[0010] In some embodiments, along the width direction of the electrode sheet, the height of the tab is H, and the height of the connector 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 point with the first side, and the second intersection point is located between the third connection point and the fourth connection point; the angle between the ray from the second intersection point to the second connection point and the ray from the second intersection point to the third connection point is α2, satisfying α2 < 90°. When viewed along the thickness direction of the tab, the line connecting the second connection point to the fourth connection point is used as the second reference line; the connecting portion also includes a main body area and a second reinforcing area, the main body area is located between the first reference line and the second reference line, and the second reinforcing area is formed by the fourth side and the second reference line.

[0012] In the above embodiments, by satisfying α2 < 90°, the second side of the electrode tab is tilted, and a second reinforcing zone is set between the fourth side and the second reference line. This helps to improve the swing stiffness and torsional stiffness of the second side of the electrode tab, thereby further suppressing the bending and insertion phenomena of the electrode tab during the production winding process, improving the production yield of the electrochemical device, and at the same time helping to reduce the risk of the electrode tab root tearing during impacts such as drops, thereby further improving the reliability of the electrochemical device.

[0013] In some embodiments, the fourth side includes a seventh side and an eighth side, with a sixth connection point between the seventh and eighth sides. The seventh side is connected to the second side, and the eighth side is connected to the first side. The included angle between the seventh and eighth sides is δ2, satisfying 90° < δ2 < 180°. Thus, the second reinforcing region has an obtuse angle structure, which is beneficial for improving the swing stiffness and torsional stiffness of the second side of the tab. This further helps to suppress bending and indentation phenomena of the tab during the production winding process, improving the production yield of the electrochemical device. Simultaneously, it helps to further reduce the risk of tearing at the root of the tab during impacts such as drops, improving the reliability of the electrochemical device.

[0014] In some embodiments, the angle between the rays from the fourth connection point to the sixth connection point and the rays from the fourth connection point to the third connection point is β2, satisfying β2≤α2<90°, and / or 60°≤β2≤90°. This improves the stiffness of the tab connection, thereby better suppressing tab swaying and torsion, increasing the production yield of the electrochemical device, and reducing the risk of tab root tearing during impacts such as drops, thus enhancing the reliability of the electrochemical device.

[0015] In some embodiments, the distance between the first and second intersection points is L; the distance between the third and fourth connection points is L1, satisfying L1≥1.1×L. This is beneficial for improving the swing stiffness and torsional stiffness of the tabs, thereby increasing the production yield of the electrochemical device and reducing the risk of tearing at the root of the tabs during impacts such as drops, thus improving the reliability of the electrochemical device.

[0016] In some embodiments, 180° - α2 < δ2 is satisfied. This increases the angle of the obtuse angle of the outer contour of the second reinforcing region, which is beneficial to further improve the swing stiffness and torsional stiffness of the electrode lug.

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

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

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

[0020] In some embodiments, the electrode is a negative electrode, which further includes a second active material layer disposed on the surface of the connecting portion. This helps to further improve the rigidity of the electrode connecting portion, thereby further suppressing bending and tearing of the electrode tab.

[0021] In some embodiments, the electrode is a positive electrode, which further includes a first insulating layer disposed on the surface of the connection portion. This helps to further improve the rigidity of the electrode connection portion, thereby further suppressing bending and tearing of the electrode tab.

[0022] In a second aspect, this application provides an electrochemical device comprising a wound electrode assembly, the electrode assembly including electrodes as described in any of the above embodiments. The improved swing stiffness and torsional stiffness of the tabs in the electrodes reduce the risk of tearing at the base of the tabs during impacts such as drops, thereby enhancing the reliability of the electrochemical device.

[0023] In a third aspect, this application provides an electrical device, which includes the electrochemical device described in the above embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an electrical device provided in an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of an electrode assembly provided in one embodiment of this application.

[0026] Figure 3 This is a front view of the electrode in its unfolded state according to an embodiment of this application.

[0027] Figure 4 A side view of the electrode in its unfolded state according to an embodiment of this application.

[0028] Figure 5 This is a schematic diagram of the base and tab provided in an embodiment of this application.

[0029] Figure 6 A partial view of the first reinforcing region shown in a connection portion provided in an embodiment of this application.

[0030] Figure 7 A partial view of the second reinforcing region shown in a connection portion provided in an embodiment of this application.

[0031] Figure 8 This is a schematic diagram of the base and trapezoidal tab in related technologies.

[0032] Figure 9 This is a schematic diagram of the base and tab provided for another embodiment of this application.

[0033] Figure 10 This is a schematic diagram of the base and tab provided in another embodiment of this application.

[0034] Figure 11 This is a schematic diagram of the base and tab provided in another embodiment of this application.

[0035] Figure 12 This is a schematic diagram of the base and tab provided in another embodiment of this application.

[0036] Explanation of main component symbols

[0037] 10mm f / 1.5 Current collector 10a First active material layer 10b Second active material layer 10c First insulating layer 10d Second insulating layer 10e Base 11 First side 111 First intersection point 111a Second intersection point 111b JE12 Extension 121 First side 1211 Second side 1212 First reference line 121a Second reference line 121b Connecting part 122 Third side 1221 Fourth side 1222 Fifth side 1223 Sixth side 1224 Seventh side 1225 Eighth side 1226 First Enhanced Zone 122a Second Enhanced Zone 122b First connection point 12a Second connection point 12b 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 1000 electrical appliances Trapezoidal tab 12' The length direction X of the electrode

[0038] The width direction Y of the electrode

[0039] Z-direction of electrode thickness Detailed Implementation

[0040] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0041] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

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

[0043] The term "parallel" is used to describe an ideal state between two components. In actual production or use, two components can exist in a state that is approximately parallel. The two components described as "parallel" do not have to be absolute straight lines or planes, but can be approximately straight lines or planes. From a macroscopic perspective, if the overall direction of extension is a straight line or plane, the component can be considered a "straight line" or "plane".

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

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0046] Some embodiments of this application will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0047] Please see Figure 1 Some embodiments of this application provide an electrical device 1000, which includes an electrochemical device 100.

[0048] In some embodiments, please refer to Figure 1 The electrical equipment 1000 also includes a main body 200, and an electrochemical device 100 is installed on the main body 200.

[0049] In some embodiments, the electrical device 1000 may be a mobile phone, laptop computer, tablet computer, drone, power tool, electric toy, game console, video recorder, portable recorder, radio, smartwatch, electric car or electric two-wheeler, etc., which will not be listed here.

[0050] In some embodiments, please refer to Figure 2 The electrochemical device 100 includes an electrode assembly 101, which includes an electrode 10, and the electrode 10 includes a positive electrode and a negative electrode.

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

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

[0053] The electrode assembly 101 can be a wound structure or a stacked structure. When the electrode assembly 101 is a wound 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 viewed 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 viewed 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, please refer to Figure 3 and Figure 4 The electrode 10 includes a base 11, which includes a current collector 10a and a first active material layer 10b. The first active material layer 10b is disposed on the surface of the current collector 10a. The electrode 10 can be a positive electrode or a negative electrode. The positive electrode includes a positive current collector and a positive active material layer. The positive current collector can be a metal layer including at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil. The positive active material layer includes a positive active material, which 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. The negative electrode 10 includes a negative current collector and a negative active material layer. The negative current collector can be a metal layer including at least one of copper, nickel, tantalum, and titanium, such as copper foil. The negative active material layer includes a negative active material, which can include at least one of graphite, hard carbon, soft carbon, silicon, silicon oxide materials, and silicon carbon materials.

[0055] In some embodiments, please refer to Figures 3 to 5 The electrode 10 includes a base 11 and an electrode tab 12 connected to each other. The electrode tab 12 includes an extension 121 and a connecting portion 122. The connecting portion 122 is located between the extension 121 and the base 11 and connects the extension 121 and the base 11.

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

[0057] In some embodiments, please refer to Figures 5 to 7Along the length direction X of the electrode 10, the base 11 includes a first side 111 connected to the tab 12. Along the length direction X of the electrode 10, the extension 121 includes a first side 1211 and a second side 1212 disposed opposite to each other, and the connecting portion 122 includes a third side 1221 and a fourth side 1222 disposed 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. A first connection point 12a is formed between the third side 1221 and the first side 1211, a second connection point 12b is formed between the fourth side 1222 and the second side 1212, a third connection point 12c is formed between the third side 1221 and the first side 111, and a fourth connection point 12d is formed between the fourth side 1222 and the first side 111. Viewed along the thickness direction Z of the tab 12, the extension of the first side 1211 intersects the first side 111 at a first intersection point 111a, which is located between the third connection point 12c and the fourth connection point 12d. The angle between the ray from the first intersection point 111a to the first connection point 12a and the ray from the first intersection point 111a to the fourth connection point 12d is α1, which satisfies α1 < 90°. Viewed along the thickness direction Z of the tab 12, with the line connecting the first connection point 12a to the third connection point 12c as the first reference line 121a, the connecting portion 122 includes a first reinforcing region 122a, which is formed by the third side 1221 and the first reference line 121a.

[0058] The inventors of this application have discovered that the tab 12 is prone to swinging or twisting under stress during production processes such as cutting and forming and winding of the electrode 10. When swinging or twisting, the tab 12 is prone to bending or insertion (leading to contact with the electrode 10 of different polarities), which seriously affects the production yield. Furthermore, the electrochemical device 100 with a multi-tab 12 structure is at increased risk of the tab 12 tearing during impacts such as drops, which affects the normal use of the electrical equipment 1000. This application achieves this by satisfying α1 < 90°, which allows the first side 1211 of the tab 12 to be inclined, and sets a first reinforcing region 122a between the third side 1221 and the first reference line 121a. This improves the swing stiffness and torsional stiffness of the first side of the tab 12, thereby suppressing bending and insertion phenomena of the tab 12 during the production winding process, improving the production yield of the electrochemical device 100, and reducing the risk of tearing at the root of the tab 12 during impacts such as drops, thus improving the reliability of the electrochemical device 100.

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

[0060] In some embodiments, please refer to Figures 5 to 7 Along the width direction Y of the electrode 10, the projection of the extension 121 is located within the projection of the connecting part 122. This makes it easier for the dimension of the connecting part 122 in the length direction X of the electrode 10 to be larger than the dimension of the extension 121 in the length direction X of the electrode 10, thereby improving the rigidity of the tab 12 and reducing the possibility of the tab 12 bending or tearing.

[0061] In some embodiments, please refer to Figures 5 to 7 Viewed along the thickness direction Z of the tab 12, the extension of the second side 1212 intersects the first side 111 at a second point 111b, which is located between the third connection point 12c and the fourth connection point 12d. The angle between the ray from the second intersection point 111b to the second connection point 12b and the ray from the second intersection point 111b to the third connection point 12c is α2, which satisfies α2 < 90°. Viewed along the thickness direction Z of the tab 12, the line connecting the second connection point 12b to the fourth connection point 12d is taken as the second reference line 121b. The connecting portion 122 also includes a main body area and a second reinforcing area 122b. The main body area is located between the first reference line 121a and the second reference line 121b, and the second reinforcing area 122b is formed by the fourth side 1222 and the second reference line 121b. By satisfying α2 < 90°, the second side 1212 of the tab 12 is inclined, and a second reinforcing region 122b is provided between the fourth side 1222 and the second reference line 121b. This helps to improve the swing stiffness and torsional stiffness of the second side of the tab 12, thereby further suppressing the bending and insertion phenomena of the tab 12 during the production winding process, improving the production yield of the electrochemical device 100, and at the same time helping to reduce the risk of tearing at the root of the tab 12 during impacts such as drops, thereby further improving the reliability of the electrochemical device 100.

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

[0063] In some embodiments, the first side 1211 and the second side 1212 can be straight or curved. When the first side 1211 and the second side 1212 are straight, the extensions of the first side 1211 and the second side 1212 are straight lines. When the first side 1211 and the second side 1212 are curved, the extensions of the first side 1211 and the second side 1212 are the tangents of the first side 1211 at the first intersection point 111a and the second side 1212 at the second intersection point 111b.

[0064] In some embodiments, please refer to Figures 5 to 7 The third side 1221 includes a fifth side 1223 and a sixth side 1224 that are connected. The fifth side 1223 is connected to the first side 1211, and the sixth side 1224 is connected to the first side 111. The included 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 reinforcing region 122a has an obtuse angle structure, which is beneficial to improving the swing stiffness and torsional stiffness of the tab 12. This is beneficial to further suppress the bending and insertion phenomena of the tab 12 during the production winding process, improve the production yield of the electrochemical device 100, and at the same time, it is beneficial to further reduce the risk of tearing at the root of the tab 12 during impacts such as drops, thereby improving the reliability of the electrochemical device 100.

[0065] For example, δ1 can be any angle among 100°, 110°, 120°, 130°, 140°, and 150°, or a range formed by any two of them.

[0066] In some embodiments, please refer to Figures 5 to 7 The condition 180° - α1 < δ1 is satisfied. When this condition is satisfied, the angle of the obtuse angle of the outer contour of the first reinforcing region 122a is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the electrode 12, and thus helps to suppress the bending and tearing of the electrode 12.

[0067] In some embodiments, please refer to Figures 5 to 7The third side 1221 includes a fifth side 1223 and a sixth side 1224 that are connected. A fifth connection point 12e is located between the fifth side 1223 and the sixth side 1224. 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 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°. Meeting this condition improves the rigidity of the tab 12 connection portion 122, thereby better suppressing the swinging and torsion of the tab 12, improving the production yield of the electrochemical device 100, and reducing the risk of tearing at the root of the tab 12 during impacts such as drops, thus enhancing the reliability of the electrochemical device 100.

[0068] For example, β1 can be any angle among 60°, 70°, 80°, 85°, and 90°, or a range formed by any two of them.

[0069] In some embodiments, please refer to Figures 5 to 7 The fourth side 1222 includes a seventh side 1225 and an eighth side 1226. A sixth connection point 12f is located between the seventh side 1225 and the eighth side 1226. The seventh side 1225 is connected to the second side 1212, and the eighth side 1226 is connected to the first side 111. The included 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 reinforcing region 122b has an obtuse angle structure, which is beneficial to improving the swing stiffness and torsional stiffness of the tab 12. This further helps to suppress bending and indentation phenomena of the tab 12 during the production winding process, improving the production yield of the electrochemical device 100. Simultaneously, it helps to further reduce the risk of tearing at the root of the tab 12 during impacts such as drops, improving the reliability of the electrochemical device 100.

[0070] For example, δ2 can be any angle among 100°, 110°, 120°, 130°, 140°, and 150°, or a range formed by any two of them.

[0071] In some embodiments, please refer to Figures 5 to 7The angle between the rays from the fourth connection point 12d to the sixth connection point 12f and the rays from the fourth connection point 12d to the third connection point 12c is β2, satisfying β2≤α2<90° and / or 60°≤β2≤90°. Meeting this condition improves the stiffness of the tab 12 connection 122, thereby better suppressing the swaying and torsion of the tab 12, thus improving the production yield of the electrochemical device 100, reducing the risk of tearing at the root of the tab 12 during impacts such as drops, and enhancing the reliability of the electrochemical device 100.

[0072] For example, β2 can be any angle among 60°, 70°, 80°, 85°, and 90°, or a range formed by any two of them.

[0073] In some embodiments, please refer to Figures 5 to 7 The condition 180° - α2 < δ2 is satisfied. When this condition is satisfied, the angle of the obtuse angle of the outer contour of the second reinforcing region 122b is increased, which is beneficial to further improve the swing stiffness and torsional stiffness of the tab 12, and thus helps to suppress the bending and tearing of the tab 12.

[0074] In some embodiments, please refer to Figures 5 to 7 The distance between the first intersection point 111a and the second intersection point 111b is L; the distance between the third connection point 12c and the fourth connection point 12d is L1, satisfying L1≥1.1×L. Meeting this condition helps to improve the rigidity of the tab 12 connection 122, suppressing the swaying and torsion of the tab, thereby improving the production yield of the electrochemical device 100, and reducing the risk of tearing at the root of the tab 12 during impacts such as drops, thus enhancing the reliability of the electrochemical device 100.

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

[0076] In some embodiments, please refer to Figure 5 and Figure 9The third side 1221 includes a broken line, which can be a double-broken line or a triple-broken line. As an example, the third side 1221 includes a fifth side 1223 and a sixth side 1224 that are connected. 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 included angle δ1 between the fifth side 1223 and the sixth side 1224, thus forming a double-broken line structure. The triple-broken line structure of the third side 1221 will not be described in detail here. Both the double-broken line structure and the triple-broken line structure of the third side 1221 are beneficial for improving the swing stiffness and torsional stiffness of the tab 12, thereby helping to suppress bending and tearing of the tab 12.

[0077] In some embodiments, please refer to Figure 10 The third side 1221 includes an arc, that is, the outer contour of the third side 1221 is arc-shaped. 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, please refer to Figure 5 and Figure 9 The fourth side 1222 includes a broken line, which can be a double-broken line or a triple-broken line. As an example, the fourth side 1222 includes a seventh side 1225 and an eighth side 1226, with a sixth connection point 12f between them. The seventh side 1225 is connected to the second side 1212, and the eighth side 1226 is connected to the first side 111. An angle δ2 exists between the seventh side 1225 and the eighth side 1226, thus forming a double-broken line structure. The triple-broken line structure of the fourth side 1222 will not be described in detail here. Both the double-broken line structure and the triple-broken line structure of the fourth side 1222 are beneficial for improving the swing stiffness and torsional stiffness of the tab 12, thereby helping to suppress bending and tearing of the tab 12.

[0079] In some embodiments, please refer to Figure 10 The fourth side 1222 includes an arc, that is, the outer contour of the fourth side 1222 is arc-shaped. 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, please refer to Figure 3 and Figure 11The electrode 10 also includes a second active material layer 10c, which is disposed on the surface of the connecting portion 122. The second active material layer 10c on the surface of the connecting portion 122 helps to distribute the stress transmitted to the tab 12, thereby increasing the rigidity of the connecting portion 122 and further suppressing the bending and tearing of the tab 12.

[0081] Understandably, the second active material layer 10c may be provided on a portion of the 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 it may be provided on the entire surface of the connecting portion 122, without any specific limitation.

[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 composition is the same as that of the aforementioned negative active material layer, which will not be repeated here.

[0083] In some embodiments, please refer to Figure 12 The electrode 10 also includes a first insulating layer 10d, which is disposed on the surface of the connecting portion 122. The first insulating layer 10d on the surface of the connecting portion 122 helps to distribute the stress transmitted to the tab 12, increasing the rigidity of the connecting portion 122 and further suppressing bending and tearing of the tab 12. Understandably, the first insulating layer 10d may be disposed on a portion of the surface of the connecting portion 122, such as the surface of the second region adjacent to the base 11 in the connecting portion 122, or it may be disposed on the entire surface of the connecting portion 122; no specific limitation is made here.

[0084] In some embodiments, the electrode 10 is a positive electrode, and the side of the current collector 10a adjacent to the tab 12 includes a third region. The electrode 10 also includes a second insulating layer 10e, which is disposed on the surface of the third region. Understandably, the second insulating layer 10e may be connected to the first insulating layer 10d.

[0085] In some embodiments, the composition of the first insulating layer 10d and the second insulating layer 10e may include inorganic particles and a binder. The composition of the first insulating layer 10d and the second insulating layer 10e may be the same or different, and no specific limitation is made here.

[0086] It should be noted that chamfers or rounded corners may exist at the intersections and connection points on the outer contour of the electrode 10 in this application, without specific limitations.

[0087] To verify the effect of the electrode sheet 10 structure of this application on improving the bending effect of the tabs 12, a comparison of the production yield improvement effect was conducted using a multi-tab 12 large soft-pack battery as an example. Each data set used 400 electrode assemblies 101, each with 98 die-cut tabs 12. The number of electrode assemblies 101 where the tabs 12 bent during the winding process was statistically analyzed. The electrode sheets in the comparative examples are as follows... Figure 8 As shown, it has a trapezoidal tab 12', with a base width L = 45mm, a slope α = 80°, and a height H = 24mm. The tab 12 in this embodiment is further reinforced based on the comparative example, with α1 = α2 = α = 80°. The base width L1, angles δ1 / δ2, β1 / β2, and the height h of the connecting portion 122 are adjusted. The test results are shown in Table 1 below:

[0088] Table 1: Comparative test data of tab 12 and trapezoidal tab 12' in this application.

[0089]

[0090]

[0091] As can be seen from the comparison between the embodiments and the comparative examples in Table 1, by adopting the electrode 10 structure of the embodiments of this application, the proportion of the electrode tab 12 of the electrode assembly 101 can be significantly reduced, thereby improving the production yield of the electrochemical device 100. At the same time, since the swing stiffness and torsional stiffness of the tab 12 are improved, the risk of the root of the tab 12 tearing during the impact of drops or other impacts on the electrochemical device 100 can be reduced, thereby improving the reliability of the electrochemical device 100.

[0092] A comparison of Examples 1-2 with Examples 2-1 to 2-3 shows that when β1≤α1<90° / β2≤α2<90° is further satisfied, it is beneficial to further improve the rigidity of the connecting part 122 of the tab 12, thereby better suppressing the swing and torsion of the tab 12, further improving the production yield of the electrochemical device 100. At the same time, it can further reduce the risk of the root of the tab 12 tearing during the impact of drops or other impacts, and improve the reliability of the electrochemical device 100.

[0093] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An electrode sheet, comprising a base and a tab, wherein along the length direction of the electrode sheet, the base includes a first side connected to the tab, characterized in that, The electrode includes: An extension portion, along the length direction of the electrode sheet, includes a first side and a second side disposed opposite to each other; A connecting portion is located between the base and the extension portion along the length direction of the electrode sheet. The connecting portion includes a third side and a fourth side disposed opposite to each other. The third side is connected to the first side and the first side, and the fourth side is connected to the first side and the second side. The third side and the first side have a first connection point, the fourth side and the second side have a second connection point, the third side and the first side have a third connection point, and the fourth side and the first side have a fourth connection point. Viewed along the thickness direction of the tab, the extension line of the first side has a first intersection point with the first side, and the first intersection point is located between the third connection point and the fourth connection point; the 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 α1, which satisfies α1 < 90°; Viewed along the thickness direction of the tab, with the line connecting the first connection point to the third connection point as the first reference line, the connection part includes a first reinforcing area, which is formed by the third side and the first reference line; The third side includes a fifth side and a sixth side. The fifth side is connected to the first side, and the sixth side is connected to the first side. The included angle between the fifth side and the sixth side is δ1, which satisfies 90°<δ1<180° and 180°-α1<δ1. Along the width direction of the electrode sheet, the height of the electrode tab is H, and the height of the connecting part is h, satisfying h / H≥1 / 5.

2. The electrode sheet according to claim 1, characterized in that, The third side includes a fifth side and a sixth side, with a fifth connection point between the fifth side and the sixth side. The fifth side is connected to the first side, and the sixth side is connected to the first side. 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°.

3. The electrode sheet according to claim 1, characterized in that, Viewed along the thickness direction of the tab, the extension line of the second side has a second intersection point with the first side, and the second intersection point is located between the third connection point and the fourth connection point; the angle between the ray from the second intersection point to the second connection point and the ray from the second intersection point to the third connection point is α2, which satisfies α2 < 90°; Viewed 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 connection part further includes a main body area and a second reinforcing area, the main body area is located between the first reference line and the second reference line, and the second reinforcing area is formed by the fourth side and the second reference line.

4. The electrode sheet according to claim 3, characterized in that, The fourth side includes a seventh side and an eighth side, with a sixth connection point 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, satisfying at least one of the following conditions: (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, which satisfies 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, which satisfies L1≥1.1×L.

5. The electrode sheet according to claim 4, characterized in that, It satisfies 180° - α² < δ².

6. The electrode sheet according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The third side includes at least one of a broken line or an arc; (2) The fourth side includes at least one of a broken line or an arc; (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 is a negative electrode, and the negative electrode further includes a second active material layer, which is disposed on the surface of the connection portion; or, the electrode is a positive electrode, and the positive electrode further includes a first insulating layer, which is disposed on the surface of the connection portion.

7. An electrochemical device, characterized in that, It includes a wound electrode assembly, the electrode assembly comprising an electrode sheet as described in any one of claims 1 to 6.

8. An electrical appliance, characterized in that, Includes the electrochemical device as described in claim 7.

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