Tab, battery device, and electric device

Abstract

The application belongs to the technical field of batteries, and provides a tab, a battery device and an electric equipment. The tab comprises a tab body and a widened portion. The tab body is used for being connected with a pole piece of the battery device. The widened portion is connected on a side of the tab body away from the pole piece along a first direction. The size of the widened portion along a second direction is greater than the size of the tab body along the second direction. The size of the widened portion along the first direction is 1 / 3-1 / 2 of the size of the tab along the first direction. The tab provided by the application can have good power performance and strength, and is convenient for assembling small-size battery devices.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a tab, a battery device, and an electrical device. Background Technology

[0002] Cylindrical lithium batteries are widely used in consumer electronics, power tools, new energy vehicles and other fields due to their advantages such as compact structure, high energy density and low manufacturing cost.

[0003] Lithium-ion batteries consist of electrodes, tabs, and current collectors. The electrodes are wound into a cylindrical shape, with the current collector located at one end. One end of the tab is connected to the electrode, and the other end is connected to the current collector. When the cross-sectional area of ​​a cylindrical lithium-ion battery is small, the cross-sectional area of ​​the tab is also small. A smaller cross-sectional area results in weaker tab strength and lower power performance of the lithium-ion battery. However, increasing the cross-sectional area of ​​the tab makes it difficult to connect the tab to a smaller cross-sectional area cylinder, hindering the assembly of small-sized lithium-ion batteries.

[0004] Therefore, there is an urgent need for a type of electrode that can have good power performance and strength, and is also easy to assemble into small-sized lithium batteries. Utility Model Content

[0005] This application provides a tab, a battery device, and an electrical device, wherein the tab has good power performance and strength, and is also convenient for assembling small-sized battery devices.

[0006] This application provides a tab, including a tab body and an extension portion. The tab body is used to connect to the electrode of a battery device. The extension portion is connected to the side of the tab body away from the electrode along a first direction. The size of the extension portion along a second direction is larger than the size of the tab body along the second direction. The size of the extension portion along the first direction is 1 / 3 to 1 / 2 of the size of the tab along the first direction.

[0007] In one possible implementation, the electrode tab provided in this application has an expansion portion whose dimension along the second direction is 1.1-1.6 times the dimension of the electrode tab body along the second direction.

[0008] In one possible implementation, the tab provided in this application includes a first welding portion and a bending portion, wherein the first welding portion is used to connect with the electrode sheet of the battery device, and the bending portion is connected with the widening portion.

[0009] In one possible implementation, the tab provided in this application has an extended portion and a portion to be bent connected by an arc transition.

[0010] In one possible implementation, the tab provided in this application further includes an extension; the extension is connected to the side of the widened portion that is away from the tab body in a first direction, and the dimension of the extension in a second direction is smaller than the dimension of the widened portion in the second direction.

[0011] In one possible implementation, the tab provided in this application has an extension and a widening portion connected by an arc transition.

[0012] In one possible implementation, the electrode tab provided in this application has an extension portion whose dimension along the second direction is equal to the electrode tab body's dimension along the second direction.

[0013] This application also provides a battery device, including an electrode and the aforementioned tab, wherein the tab body is connected to the electrode, and the widened portion of the tab is connected along a first direction to the side of the tab body opposite to the electrode.

[0014] In one possible implementation, the battery device provided in this application includes a tab body comprising a first welding portion and a bending portion, wherein the first welding portion is stacked on the electrode sheet and connected to the electrode sheet; and the bending portion extends beyond the edge of the electrode sheet.

[0015] In one possible implementation, the battery device provided in this application further includes a widened portion and an extended portion in the tab, with the first welding portion, the bending portion, the widened portion and the extended portion connected in sequence.

[0016] In one possible implementation, the battery device provided in this application includes an electrode sheet comprising a current collector and an active material layer. The current collector has a coating portion and a second welding portion. The active material layer is coated on the coating portion, and a first welding portion is stacked on the second welding portion and welded to the second welding portion.

[0017] In one possible implementation, the battery device provided in this application has a plurality of second welding portions on the electrode sheet, the plurality of second welding portions being arranged at intervals along the length direction of the electrode sheet, and the battery device includes a plurality of tabs, wherein the first welding portion of the tab and the second welding portion are connected in a one-to-one correspondence; wherein, on the unfolded electrode sheet, the length direction of the electrode sheet is consistent with the second direction.

[0018] In one possible implementation, the battery device provided in this application has an electrode sheet with a length dimension of L and a number of tabs of n on the unfolded electrode sheet. The distance between the tabs near the edge of the electrode sheet and the edge of the electrode sheet along the length direction of the electrode sheet is f = (1 / 2n) × L. The multiple tabs are evenly spaced along the length direction of the electrode sheet.

[0019] And / or, the dimension of the second weld portion along the length of the unfolded electrode sheet is less than half the circumference of the second weld portion at the ring where the second weld portion is located after the electrode sheet is wound.

[0020] And / or, the dimension of the widened portion along the length of the unfolded electrode sheet is less than half the circumference of the second welded portion corresponding to the widened portion at the location of the ring after the electrode sheet is wound.

[0021] And / or, on the unfolded electrode, the dimension of the first weld portion along the length direction of the electrode is 50%-85% of the dimension of the second weld portion along the length direction of the electrode;

[0022] And / or, the dimension of the electrode body along the first direction is 80%-120% of the dimension of the second welded part along the first direction;

[0023] And / or, the thickness of the first welded portion is 30%-150% of the thickness of the active material layer.

[0024] In one possible implementation, the battery device provided in this application further includes a current collector, and the widened portion is connected to the current collector;

[0025] Alternatively, the tab may also include an extension connected to the side of the widened portion away from the tab body along a first direction, and the extension is connected to the collector plate.

[0026] This application also provides an electrical device including the aforementioned battery device.

[0027] The tab provided in this application comprises a tab body and a widened portion. The tab body is used to connect to the electrode sheet. The widened portion is connected along a first direction to the side of the tab body opposite to the electrode sheet. The dimension of the widened portion along a second direction is larger than the dimension of the tab body along the second direction. This facilitates the connection between the tab and the electrode sheet and improves the power performance and strength of the tab. The dimension of the widened portion along the first direction is 1 / 3 to 1 / 2 of the dimension of the tab along the first direction. By limiting the dimension of the widened portion along the first direction, the connection between the tab and the electrode sheet can be made more reliable while further improving the strength and power performance of the tab. Therefore, the tab provided in this application has both good power performance and strength, and is convenient for assembling small-sized battery devices. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0030] Figure 2 This is a schematic diagram of the internal structure of the battery device provided in an embodiment of this application;

[0031] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0032] Figure 4 A schematic diagram of the electrode sheet and tab in the unfolded state of the battery device provided in the embodiment of this application;

[0033] Figure 5 This is a schematic diagram of the winding process of the battery device provided in the embodiments of this application;

[0034] Figure 6 A schematic diagram of the electrode structure provided in the embodiments of this application;

[0035] Figure 7 for Figure 6 The front view;

[0036] Figure 8 for Figure 6 Side view;

[0037] Figure 9 A schematic cross-sectional view of the electrode and tab in the battery device provided in the embodiments of this application;

[0038] Figure 10 This is a schematic diagram of the structure of the electrode in the battery device provided in the embodiments of this application;

[0039] Figure 11 Another structural schematic diagram of the electrode and tab in the unfolded state of the battery device provided in the embodiment of this application;

[0040] Figure 12 This is a top view of the battery device provided in the embodiments of this application after the electrode sheets are wound.

[0041] Explanation of reference numerals in the attached figures:

[0042] 10-Battery Device;

[0043] 100 - Electrode; 100a - Long side; 100b - Short side;

[0044] 110 - Current collector; 111 - Coating part; 112 - Second welding part;

[0045] 120 - Active material layer;

[0046] 200-collector disk;

[0047] 300-pole ear;

[0048] 310 - Electrode body; 311 - First welding part; 312 - Part to be bent;

[0049] 320 - Widening section;

[0050] 330 - Extension;

[0051] 400 - Outer shell; 500 - Diaphragm; 600 - Cover plate;

[0052] a - First dimension; b - Second dimension; B - Third dimension; c - Fourth dimension; a1 - Fifth dimension; h - Sixth dimension; d - Seventh dimension; i - Eighth dimension; e - Ninth dimension; j - Tenth dimension;

[0053] f - first spacing; g - second spacing;

[0054] Ax - Axial direction; C - Circumferential direction; D - Radial direction;

[0055] X - First direction; Y - Second direction; Z - Thickness direction. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0058] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0059] The terms "first," "second," and "third" (if any) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0060] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or maintenance tool that includes a series of steps or units, not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or maintenance tool.

[0061] Cylindrical lithium batteries are widely used in consumer electronics, power tools, new energy vehicles and other fields due to their advantages such as compact structure, high energy density and low manufacturing cost.

[0062] A lithium battery consists of electrodes, tabs, and current collectors. The electrodes are wound into a cylindrical shape, with the current collector located at one end. One end of the tab is connected to the electrode, and the other end is connected to the current collector. When the cross-sectional area of ​​a cylindrical lithium battery is small, the cross-sectional area of ​​the tab is also small.

[0063] When the cross-sectional area of ​​the tab is small, the current path between the electrode and the current collector is narrow, increasing the internal resistance of the lithium battery and leading to a decrease in the power performance of the lithium-ion battery. After bending, the tab is electrically connected to the current collector. The small cross-sectional area of ​​the tab makes it prone to breakage, deformation, or poor welding at the bending point towards the current collector, resulting in poor tab strength. However, increasing the cross-sectional area of ​​the tab makes it difficult to connect to smaller cross-sectional area cylinders, hindering the assembly of small-sized lithium batteries.

[0064] Therefore, there is an urgent need for a type of electrode that can have good power performance and strength, and is also easy to assemble into small-sized lithium batteries.

[0065] Based on this, embodiments of this application provide a tab, a battery device, and an electrical device. The tab can have good power performance and strength, and is also convenient for assembling small-sized battery devices.

[0066] Figure 1 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application; Figure 2 This is a schematic diagram of the internal structure of the battery device provided in an embodiment of this application; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 A schematic diagram of the electrode sheet and tab in the unfolded state of the battery device provided in the embodiment of this application; Figure 5 This is a schematic diagram of the winding process of the battery device provided in the embodiments of this application.

[0067] See Figures 1 to 5 As shown, the battery device 10 includes an electrode 100 and a tab 300. One end of the tab 300 is connected to the electrode 100, and the other end of the tab 300 extends away from the electrode 100 to connect the electrode 100 to a charging and discharging device.

[0068] Specifically, the battery device 10 can be a lithium-ion battery or other types of batteries. This application uses a lithium-ion battery as an example for illustration.

[0069] Please continue reading Figures 1 to 3 As shown, the battery device 10 also includes a housing 400, which can be a cuboid, cylinder, or elliptical cylinder, etc. Figure 1 and Figure 2 In the embodiment shown, the outer casing 400 is a cylinder. The outer casing 400 has an axial direction Ax, a circumferential direction C, and a radial direction D.

[0070] Please continue reading Figure 5 As shown, the battery device 10 may include two electrodes 100 with opposite polarities; for example, one electrode 100 may be a positive electrode and the other electrode 100 may be a negative electrode. The battery device 10 also includes a separator 500, with the two electrodes 100 located on opposite sides of the separator 500. After the electrodes 100 and the separator 500 are wound into a cylindrical battery cell, they are installed into a housing 400, and an electrolyte is injected into the housing 400.

[0071] Please continue reading Figure 1 and Figure 2 As shown, the battery device 10 also includes a cover plate 600, which is disposed along the axial direction Ax on both ends of the cylindrical housing 400. The cover plate 600 can be connected to the housing 400 to prevent electrolyte leakage or the battery cell from coming out of the housing 400.

[0072] During charging, lithium ions from the positive electrode and the electrolyte pass through the separator to the negative electrode, where they gain electrons and are reduced to lithium, which is then embedded in the negative electrode. During discharging, the lithium embedded in the negative electrode loses electrons and enters the electrolyte, while the lithium ions in the electrolyte return to the positive electrode. This cycle continues, completing the charging and discharging process of a lithium-ion battery.

[0073] In some battery devices 10, the end of the tab 300 facing away from the electrode 100 is directly connected to the charging and discharging equipment. In other battery devices 10, the end of the tab 300 facing away from the electrode 100 is connected to the charging and discharging equipment via an adapter. In some battery devices 10, the adapter is a current collector 200. The following explanation uses the current collector 200 as an example.

[0074] Please continue reading Figures 2 to 4As shown, the current collector 200 is located between the cover plate 600 and the battery cell, and the cover plate 600 is connected to the electrode 100 through the current collector 200. Specifically, the battery device 10 also includes a tab 300, one end of which is electrically connected to the electrode 100. After the electrode 100 is wound and the tab 300 is bent, the other end of the tab 300 is connected to the current collector 200. Thus, the electrode 100 and the cover plate 600 can be electrically connected through the tab 300 and the current collector 200. After the cover plate 600 is connected to a charging and discharging device, it can be charged and discharged.

[0075] Figure 6 A schematic diagram of the electrode structure provided in the embodiments of this application; Figure 7 for Figure 6 The front view; Figure 8 for Figure 6 Side view.

[0076] See Figure 4 as well as Figures 6 to 8 As shown, the tab 300 includes a tab body 310 and a widening portion 320. The tab body 310 is used to connect with the electrode 100. The widening portion 320 is connected to the side of the tab body 310 away from the electrode 100 along a first direction X. The size of the widening portion 320 along a second direction Y is larger than the size of the tab body 310 along the second direction Y. The size of the widening portion 320 along the first direction X is 1 / 3 to 1 / 2 of the size of the tab 300 along the first direction X.

[0077] Before the electrode 100 is wound and before the tab 300 is bent, the first direction X is the width direction of the electrode 100, and the second direction Y is the length direction of the electrode 100. The side of the electrode 100 extending along the length direction is the long side 100a, and the side of the electrode 100 extending along the width direction is the short side 100b. When the electrode 100 is wound, it is wound along the long side 100a with one of the short sides 100b as the axis. After the electrode 100 is wound, the axial direction Ax is consistent with the width direction of the electrode 100, and the two short sides 100b of the electrode 100 face the two cover plates 600 of the two battery devices 10 respectively. The tab 300 also has a thickness direction Z, which is an angle with both the first direction X and the second direction Y. The thickness direction Z of the electrode 100 is consistent with the thickness direction of the tab 300.

[0078] The tab 300 includes a tab body 310, which can be welded to the electrode 100 from one long side 100a. The tab body 310 has a first dimension a along the second direction Y. When the radius of the battery device 10 is small, the size of the electrode 100 after winding is small. Therefore, if the first dimension a of the tab body 310 is set too large, it will be inconvenient for the winding of the electrode 100.

[0079] The tab 300 also includes a widened portion 320, which is connected to the side of the tab body 310 opposite to the electrode plate 100, and the projection of the widened portion 320 along the thickness direction of the electrode plate 100 does not coincide with the electrode plate 100. After the tab 300 is bent at a certain position on the tab body 310, the widened portion 320 on the side of the tab 300 opposite to the tab body 310 can be used to connect to the collector plate 200.

[0080] The dimension of the widened portion 320 along the second direction Y is a second dimension b, which is larger than the first dimension a. This reduces the internal resistance of the tab 300, thereby improving its power performance. The fact that the second dimension b is larger than the first dimension a also makes the side of the tab 300 facing the current collector 200 stronger, reducing the probability of the tab 300 breaking or deforming and poor welding.

[0081] The tab 300 has a third dimension B along the first direction X, and the widened portion 320 has a fourth dimension c along the first direction X. When c < 1 / 3 × B, the area of ​​the widened portion 320 is small, and the improvement in the strength and power performance of the tab 300 is not significant. When c > 1 / 2 × Bn, the widened portion 320 occupies a larger dimension along the first direction X, which makes the tab body 310 occupy a smaller dimension along the first direction X. The welding area between the tab body 310 and the electrode 100 is reduced, the welding is unreliable, and the area of ​​the tab body 310 used for bending is reduced, making it inconvenient to bend the tab 300.

[0082] Therefore, in this embodiment, 1 / 3×B≤c≤1 / 2×B is made so that the strength and power performance of the tab 300 can be improved, and the tab 300 can be easily connected to the electrode 100.

[0083] The tab 300 provided in this embodiment of the application includes a tab body 310 and a widening portion 320. The tab body 310 is used to connect with the electrode 100. The widening portion 320 is connected along a first direction X to the side of the tab body 310 opposite to the electrode 100. The dimension of the widening portion 320 along a second direction Y is larger than the dimension of the tab body 310 along the second direction Y. This facilitates the connection between the tab 300 and the electrode 100 and improves the power performance and strength of the tab 300. The dimension of the widening portion 320 along the first direction X is 1 / 3 to 1 / 2 of the dimension of the tab 300 along the first direction X. By limiting the dimension of the widening portion 320 along the first direction X, the connection between the tab 300 and the electrode 100 can be made more reliable while further improving the strength and power performance of the tab 300. Therefore, the tab 300 provided in this embodiment of the application has good power performance and strength, and is also convenient for the assembly of small-sized battery devices 10.

[0084] In one possible implementation, the dimension of the widened portion 320 along the second direction Y is 1.1 to 1.6 times the dimension of the tab body 310 along the second direction Y.

[0085] When the second dimension b is too small, the improvement in strength and power performance is limited. When the second dimension b is too large, the actual current flowing through the widened portion 320 is limited, resulting in waste of the raw materials for the tab 300 and a higher cost for the battery device 10. Therefore, in this embodiment, the second dimension b can be set according to the specific value of the first dimension a, such that the second dimension b is 1.1-1.6 times the first dimension a. This effectively improves the strength and power performance of the tab 300 while avoiding excessive cost for the battery device 10.

[0086] Please continue reading Figure 4 as well as Figures 6 to 8 As shown, the tab body 310 includes a first welding part 311 and a bending part 312. The first welding part 311 is used to connect with the electrode 100 of the battery device 10, and the bending part 312 is connected with the widening part 320.

[0087] The first welding portion 311, the bending portion 312, and the widening portion 320 are connected sequentially. The projection of the first welding portion 311 along the thickness direction Z can overlap with the electrode 100. The first welding portion 311 is used for welding with the electrode 100. The bending portion 312 extends from the first welding portion 311 toward the widening portion 320, that is, the bending portion 312 extends beyond the edge of the electrode 100, so that the projection of the bending portion 312 along the thickness direction Z does not overlap with the electrode 100. By reserving the bending portion 312 in the tab body 310, after the first welding portion 311 is welded to the electrode 100, the tab body 310 can be bent from the bending portion 312, which can prevent the tab 300 from having insufficient welding strength with the electrode 100 due to bending.

[0088] In one possible implementation, the widened portion 320 and the portion to be bent 312 are connected by an arc transition. The arc length can be 1 / 8 to 1 / 4 of the circumference of the circle containing the arc. Figure 6 and Figure 7 In the embodiment shown, the arc length is 1 / 4 of the circumference of the circle containing the arc.

[0089] Therefore, the first dimension a can be gradually increased to the second dimension b, and the arc transition connection can reduce stress concentration at the connection between the widened portion 320 and the portion to be bent 312, thereby increasing the strength at the connection between the widened portion 320 and the portion to be bent 312. The arc transition connection between the widened portion 320 and the portion to be bent 312 can also reduce the skin effect of the current, avoiding an increase in the resistance of the tab 300 due to the skin effect.

[0090] Please continue reading Figure 4 as well as Figures 6 to 8 As shown, the tab 300 also includes an extension 330 for connecting to the current collector 200 of the battery device 10; the extension 330 is connected to the side of the widened portion 320 opposite to the tab body 310 along the first direction X, and the dimension of the extension 330 along the second direction Y is smaller than the dimension of the widened portion 320 along the second direction Y.

[0091] The extension 330 has a fifth dimension a1 along the second direction Y, which is smaller than the second dimension b. After the tab 300 is bent at the bending portion 312, the extension 330 is welded to the current collector 200. When the size of the battery device 10 is small, the area of ​​the current collector 200 is also small. If the size of the extension 330 is too large, the contact area between the extension 330 and the current collector 200 is still limited. Therefore, an excessively large extension 330 will result in a waste of raw materials. In this embodiment, the dimension of the extension 330 along the second direction Y is made smaller than the dimension of the widened portion 320 along the second direction Y, which can reduce the cost of the tab 300 and thus reduce the cost of the battery device 10.

[0092] In one possible implementation, the extension 330 and the widening portion 320 are connected by an arc transition. This increases the strength at the connection between the widening portion 320 and the extension 330. It also reduces the skin effect of the current at the connection between the widening portion 320 and the extension 330, further reducing the resistance of the tab 300.

[0093] Alternatively, the bending portion 312 can be disposed between the extension portion 330 and the widening portion 320. After the tab 300 is bent in the bending portion 312 between the extension portion 330 and the widening portion 320, the extension portion 330 is welded to the collector plate 200.

[0094] In one possible implementation, the dimension of the extension 330 along the second direction Y is equal to the dimension of the tab body 310 along the second direction Y. That is, the first dimension a is equal to the fifth dimension a1, thereby reducing the number of dimensions that need to be controlled during the manufacturing process of the tab 300 and lowering the manufacturing cost of the tab 300.

[0095] Figure 9 A schematic cross-sectional view of the electrode and tab in the battery device provided in the embodiments of this application; Figure 10 This is a schematic diagram of the structure of the electrode in the battery device provided in the embodiments of this application.

[0096] See Figure 9 and Figure 10As shown, the electrode 100 includes a current collector 110 and an active material layer 120. The current collector 110 has a coating portion 111 and a second welding portion 112. The active material layer 120 is coated on the coating portion 111. A first welding portion 311 is stacked on the second welding portion 112 and welded to the second welding portion 112.

[0097] When electrode 100 is a positive electrode, current collector 110 can be aluminum or an aluminum alloy, and active material layer 120 can be lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), etc. When electrode 100 is a negative electrode, current collector 110 can be copper or a copper alloy, and active material layer 120 can be graphite-based materials, silicon-based materials, etc.

[0098] The active material layer 120 can be coated on one side of the current collector 110 along the thickness direction, or it can be coated on both sides of the current collector 110 along the thickness direction Z. Then, a portion of the active material layer is washed away to expose the current collector 110. The area on the current collector 110 covered with the active material layer 120 is the coating part 111, and the area on the current collector 110 used for welding with the tab 300 is the second welding part 112.

[0099] When welding tab 300 and electrode 100, the first welding part 311 is stacked on the second welding part 112, and then the first welding part 311 is welded to the second welding part 112.

[0100] Please continue reading Figure 4 and Figure 10 As shown, the electrode 100 has a plurality of second welding portions 112, which are arranged at intervals along the length of the electrode 100. There are also a plurality of tabs 300, and the first welding portion 311 of the tab 300 is connected to the second welding portion 112 in a one-to-one correspondence.

[0101] The second welding part 112 can be two or more, in Figure 4 and Figure 10 Two second welded portions 112 are schematically shown, and correspondingly, the number of tabs 300 is also two. Multiple tabs 300 can shorten the current transmission distance from the active material layer 120 to the current collector 110, reduce the electron conduction path inside the electrode 100, and thus reduce resistance.

[0102] Multiple tabs 300 can also avoid current concentration caused by a single tab 300, thereby reducing local overcurrent and heat generation. Low internal resistance and uniform current distribution make the battery device 10 more suitable for fast charging and high power output scenarios, which can improve the power performance of the battery device 10.

[0103] Figure 11This is another structural schematic diagram of the electrode and tab in the unfolded state of the battery device provided in the embodiments of this application.

[0104] See Figure 11 As shown, on the unfolded electrode 100, the dimension of the electrode 100 along its length direction is L, the number of tabs is n, the distance between the tabs 300 near the edge of the electrode 100 along the length direction of the electrode 100 and the edge of the electrode 100 is f = (1 / 2n) × L, and multiple tabs 300 are evenly spaced along the length direction of the electrode 100.

[0105] The impedance R of electrode 100 Ω The calculation can be performed using the following formula:

[0106]

[0107] Where I is the current, n is the number of tabs 300 on the electrode 100, t is the charging and discharging time, ρ is the conductivity coefficient, and S is the cross-sectional area of ​​the tab 300.

[0108] After simplifying the above formula, the minimum impedance R can be obtained. Ωmin The calculation formula is as follows:

[0109]

[0110] The distance between the tab 300 near the edge of the electrode 100 and the edge of the electrode 100 is the first spacing f. When the first spacing f = (1 / 2n) × L, the impedance value is the minimum.

[0111] For example, when there are two tabs 300, the first spacing f = (1 / 4) × L. When there are three tabs 300, the first spacing f = (1 / 6) × L. When there are four tabs 300, the first spacing f = (1 / 8) × L.

[0112] The spacing between multiple tabs 300 located in the middle region of the electrode 100 along its length is called the second spacing g, which can be understood as g = (1 / n) × L. For example, when there are two tabs 300, the second spacing g = (1 / 2) × L. When there are three tabs 300, the second spacing g = (1 / 3) × L. When there are four tabs 300, the second spacing g = (1 / 4) × L.

[0113] Figure 12 This is a top view of the battery device provided in the embodiments of this application after the electrode sheets are wound.

[0114] See Figure 11 and Figure 12As shown, in one possible implementation, the dimension of the second welding portion 112 on the unfolded electrode 100 along the length direction of the electrode 100 is less than half the circumference of the second welding portion 112 at the ring where the second welding portion 112 is located after the electrode 100 is wound.

[0115] It is understandable that after the electrode 100 is wound, different second welding portions 112 are located on different winding rings. Specifically, the dimension of the second welding portion 112 along the length direction of the electrode 100 is a sixth dimension h, and the radius of the ring where one of the second welding portions 112 is located after the electrode 100 is wound is r. The sixth dimension h and the radius r can satisfy the following relationship: h < 50% * 2πr, that is, the sixth dimension h is less than half the circumference of the ring where the second welding portion 112 is located. Therefore, after the first welding portion 311 of the electrode tab 300 is stacked on the second welding portion 112, the winding of the electrode 100 can be facilitated.

[0116] Please continue reading Figure 7 , Figure 11 and Figure 12 As shown, in one possible implementation, the dimension of the widened portion 320 along the length direction of the unfolded electrode 100 is less than half the circumference of the second weld portion 112 corresponding to the widened portion 320 at the location of the ring after the electrode 100 is wound.

[0117] The dimension of the widened portion 320 along the second direction Y is the second dimension b. The radius of the ring where one of the second welding portions 112 of the electrode sheet 100 is located after winding is r. The second dimension b and the radius r can satisfy the following relationship: b < 50% * 2πr. This is because when b ≥ 50% * 2πr, it is difficult to bend the tab 300 when the electrode sheet 100 is wound, and problems such as breakage or tearing of the tab 300 are likely to occur.

[0118] In one possible implementation, on the unfolded electrode 100, the dimension of the first weld portion 311 along the length direction of the electrode 100 is 50%-85% of the dimension of the second weld portion 112 along the length direction of the electrode 100.

[0119] The dimension of the first welded portion 311 along the length of the electrode 100 is the dimension of the tab body 310 along the second direction Y (first dimension a). When the first dimension a is less than 50% of the sixth dimension h, the current collector 110 is exposed in too large an area, resulting in a reduction in the effective size of the electrode 100. Furthermore, a smaller first dimension a will increase the temperature at the connection between the electrode 100 and the tab 300. When the first dimension a is greater than 80% of the sixth dimension h, the welding precision requirement for the tab 300 is too high, making welding difficult and costly.

[0120] Please continue reading Figure 7 and Figure 11As shown, in one possible implementation, before the tab 300 is bent, the size of the tab body 310 along the first direction X is 80%-120% of the size of the second welded part 112 along the first direction X.

[0121] The electrode body 310 has a seventh dimension d along the first direction X, and the second welding part 112 has an eighth dimension i along the first direction X. When the seventh dimension d is too large, the welding precision requirement for the electrode 300 is too high, making welding difficult and costly. When the seventh dimension d is too small, the size of the first welding part 311 is too small, resulting in a small welding area between the first welding part 311 and the second welding part 112. Please refer to [further details omitted]. Figure 7 As shown, the seventh dimension d is the sum of the dimensions of the part to be bent 312 and the first welding part 311 along the first direction X. The seventh dimension d is small, which makes the dimension of the part to be bent 312 along the first direction X also small, which is not convenient for bending the tab 300. Therefore, in this embodiment, the seventh dimension d and the eighth dimension i can satisfy the following relationship: d = (80% - 120%) × i.

[0122] Please continue reading Figure 8 and Figure 9 As shown, in one possible implementation, the thickness of the first weld portion 311 is 30%-150% of the thickness of the active material layer 120.

[0123] The thickness of the first weld portion 311 is the ninth dimension e, and the thickness of the active material layer 120 is the tenth dimension j. When the ninth dimension e is less than 30% of the tenth dimension j, the thickness of the tab 300 is small, resulting in a large temperature rise in the battery device 10, and the weldability is poor when the first weld portion 311 is too thin. When the ninth dimension e is greater than 150% of the tenth dimension j, the thickness of the tab 300 is large, making lithium plating more likely to occur at the corresponding positions of the electrode 100 and the tab 300, thereby reducing the capacity of the battery device 10. Therefore, in the embodiments of this application, the ninth dimension e and the tenth dimension j can satisfy the following relationship: 30%j≤e≤150%j.

[0124] The battery device 10 provided in this application will be further described below through specific embodiments.

[0125] Example 1

[0126] The active material layer 120 of the positive electrode includes lithium iron phosphate, lithium supplement, conductive agent, thickener (e.g., polyvinylidene fluoride, PVDF), and additives (e.g., lithium nickel oxide, LiNiO2, LNO). The active material layer 120 of the negative electrode includes graphite powder, additives, conductive agent, thickener (e.g., sodium carboxymethyl cellulose, CMC), and emulsion. The separator 500 can be made of polypropylene (PP). The electrolyte composition includes lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), and vinylene carbonate (VC).

[0127] The following explanation uses an example of two tabs 300 on each electrode 100. The dimensions of the positive electrode are indicated by the subscript "positive". The dimensions of the negative electrode are indicated by the subscript "negative". The dimensions of the two second welding parts 112 are distinguished by the subscripts "1" and "2".

[0128] The dimensions of the positive and negative electrodes are as follows:

[0129] L 正 =1500mm, L 负 =1600mm, h 1正 =h 2正 =h 1负 =h 2负 =8mm, i 1正 =i 2正 =i 1负 =i 2负 =15mm, f 正 =396mm, f 负 =396mm, j 正 =140μm, j 负 =120μm.

[0130] The dimensions of the tabs 300 are as follows: the dimension B of one tab 300 on the positive electrode plate along the first direction X is 36mm, and the dimension B of the other tab 300 on the positive electrode plate along the first direction X is 38mm.

[0131] The dimensions of the Electrode 300 are as follows:

[0132] B 1正 =36mm, B 2正 =38mm, B 1负 =36mm, B 2负 =37mm, a 1正 =a2正 =5mm, a 1负 =a 2负 =6mm, e 1正 =e 2正 =0.1mm, e 1负 =e 2负 =0.08mm, d 1正 =d 2正 =d 1负 =d 2负 =12mm, c 1正 =c 2正 =c 1负 =c 2负 =14mm, b 1正 =7mm; b 2正 =9mm, b 1负 =8mm, b 2负 =10mm.

[0133] The positive electrode, separator 500, and negative electrode are stacked and wound in sequence. The positive electrode is wound 20 times and the negative electrode is wound 21 times to obtain a core structure. The dimension of the positive electrode along the first direction X is 58mm, the dimension of the negative electrode along the first direction X is 60mm, and the dimension of the separator 500 along the first direction X is 62mm. After assembly, the battery device 10 is obtained.

[0134] In Example 1, two battery devices 10 were prepared, and the two battery devices 10 were numbered Example 1.1# and Example 1.2#, respectively.

[0135] Comparative Example 1

[0136] The preparation conditions for Comparative Example 1 were the same as those for Example 1, except that Comparative Example 1 used a rectangular tab, and the projection of the tab 300 along the thickness direction Z was rectangular, where a refers to the dimension of the tab along the second direction, B refers to the dimension of the tab along the first direction, and e refers to the dimension of the tab along the thickness direction. That is, a 1正 =a 2正 =5mm, a 1负 =a 2负 =6mm, where, e 1正 =e 2正 =0.1mm, e 1负 =e 2负 =0.08mm, B 1正 =36mm, B 2正 =38mm, B 1负 =36mm, B 2负 =37mm.

[0137] In Comparative Example 1, two battery devices were prepared, which were numbered Comparative Example 1.1# and Comparative Example 1.2#, respectively.

[0138] The battery devices of Example 1 and Comparative Example 1 were subjected to cold start discharge tests. The test methods are as follows:

[0139] 1. The battery device 10 is charged at a constant voltage of 3.45V, with a maximum current limit of 5.2C and a cutoff current of 0.05C (when the battery is at 100% state of charge);

[0140] 2. The battery device 10 is discharged at 1C for 48 minutes, and the state of charge is adjusted to 20%;

[0141] 3. The battery device 10 is placed at -25 degrees Celsius for 60 minutes;

[0142] 4. The battery device is left to rest for 1 minute, during which data is collected every 1 second; then it is discharged with a current of 1.67C for 9 seconds, and then discharged with a current of 2.5C for 2 seconds, during which voltage data is collected every 100ms; then it is left to rest for 5 minutes, during which data is collected every 1 second.

[0143] 5. The battery device 10 is placed at -30 degrees Celsius for 60 minutes;

[0144] 6. Let it rest for 1 minute, and collect data every 1 second; discharge with a current of 1.67C for 9 seconds, then discharge with a current of 2.5C for 2 seconds, and collect voltage data every 100ms during the discharge; let it rest for another 5 minutes, and collect data every 1 second during the rest period.

[0145] The cold start discharge test results of the battery devices in Example 1 and Comparative Example 1 are shown in Table 1 below:

[0146] Table 1 Results of Cold Start Discharge Capability under Multiple Temperatures

[0147]

[0148] A comparison of Example 1 and Comparative Example 1 shows that the discharge voltage of both Examples 1 at -25°C is greater than that of both Comparative Examples 1 at -25°C. Similarly, the discharge voltage of both Examples 1 at -30°C is greater than that of both Comparative Examples 1 at -30°C. Compared to rectangular tabs in related technologies, the tab 300 provided in this application can effectively improve the power performance of the battery cell and reduce its impedance.

[0149] Comparative Example 2

[0150] The preparation conditions for Comparative Example 2 were the same as those for Example 1. Comparative Example 2 used the tab 300 provided in the embodiments of this application. The difference between Comparative Example 2 and Example 1 was the position of the tab 300, i.e., f. 正 =450mm, f 负 =450mm.

[0151] In Comparative Example 2, two battery devices were prepared, which were numbered Comparative Example 2.1# and Comparative Example 2.2#, respectively.

[0152] Comparative Example 3

[0153] The preparation conditions for Comparative Example 3 were the same as those for Example 1. Comparative Example 3 used the tab 300 provided in the embodiments of this application. The difference between Comparative Example 3 and Example 1 was the position of the tab 300, i.e., f. 正 =450mm, f 负 =450mm.

[0154] In Comparative Example 3, two battery devices were prepared, which were numbered Comparative Example 3.1# and Comparative Example 3.2#, respectively.

[0155] The cold start discharge test results of the battery devices in Example 1, Comparative Example 2, and Comparative Example 3 are shown in Table 2 below:

[0156] Table 2 Results of Cold Start Discharge Capability under Multiple Temperatures

[0157]

[0158] The comparison results between Example 1 and Comparative Examples 2 and 3 show that the discharge voltage of Example 1 at -25°C is greater than that of Comparative Examples 2 and 3 at -25°C. The discharge voltage of Example 1 at -30°C is also greater than that of Comparative Examples 2 and 3 at -30°C. Therefore, it can be concluded that when the first spacing f = (1 / 2n)*L, the battery device 10 has better power performance.

[0159] This application also provides an electrical device, including the battery device 10 provided in the above embodiments.

[0160] The specific structure of the battery device 10 has been described in detail in the above embodiments, and will not be repeated here.

[0161] Electrical equipment can be devices powered by batteries, such as laptops, vehicles, aircraft, ferries, computers, or energy storage cabinets. Vehicles can be electric vehicles (EVs), pure electric vehicles (PEVs / BEVs), hybrid electric vehicles (HEVs), range-extended electric vehicles (REEVs), plug-in hybrid electric vehicles (PHEVs), or new energy vehicles.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A type of electrode, characterized in that, include: A tab body (310) is used to connect to the electrode (100) of the battery device (10); An enlarged portion (320) is connected along a first direction to the side of the tab body (310) opposite to the electrode plate (100). The size of the enlarged portion (320) along a second direction is larger than the size of the tab body (310) along the second direction. The size of the enlarged portion (320) along the first direction is 1 / 3 to 1 / 2 of the size of the tab (300) along the first direction.

2. The electrode tab according to claim 1, characterized in that, The dimension of the widened portion (320) along the second direction is 1.1-1.6 times the dimension of the tab body (310) along the second direction.

3. The electrode tab according to claim 1, characterized in that, The tab body (310) includes a first welding part (311) and a bending part (312). The first welding part (311) is used to connect with the electrode (100) of the battery device (10), and the bending part (312) is connected with the widening part (320).

4. The electrode tab according to claim 3, characterized in that, The widened portion (320) and the portion to be bent (312) are connected by an arc transition.

5. The electrode tab according to any one of claims 1 to 4, characterized in that, It also includes an extension (330); the extension (330) is connected to the side of the widened portion (320) away from the tab body (310) along the first direction, and the dimension of the extension (330) along the second direction is smaller than the dimension of the widened portion (320) along the second direction.

6. The electrode tab according to claim 5, characterized in that, The extension (330) and the widening (320) are connected by an arc transition.

7. The electrode tab according to claim 5, characterized in that, The dimension of the extension (330) along the second direction is equal to the dimension of the tab body (310) along the second direction.

8. A battery device, characterized in that, Includes an electrode plate (100) and an electrode tab (300) as described in any one of claims 1 to 7, wherein the electrode tab body (310) of the electrode tab (300) is connected to the electrode plate (100), and the widened portion (320) of the electrode tab (300) is connected along a first direction to the side of the electrode tab body (310) opposite to the electrode plate (100).

9. The battery device according to claim 8, characterized in that, The electrode body (310) includes a first welding part (311) and a bending part (312), wherein the first welding part (311) is stacked on the electrode (100) and connected to the electrode (100); The portion to be bent (312) extends beyond the edge of the electrode (100).

10. The battery device according to claim 9, characterized in that, The tab (300) further includes a widening portion (320) and an extension portion (330), wherein the first welding portion (311), the bending portion (312), the widening portion (320) and the extension portion (330) are connected in sequence.

11. The battery device according to claim 8, characterized in that, The electrode (100) includes a current collector (110) and an active material layer (120). The current collector (110) has a coating portion (111) and a second welding portion (112). The active material layer (120) is coated on the coating portion (111). The electrode body (310) includes a first welding portion (311). The first welding portion (311) is stacked on the second welding portion (112) and welded to the second welding portion (112).

12. The battery device according to claim 11, characterized in that, The electrode (100) has a plurality of second welding portions (112), which are spaced apart along the length of the electrode (100). The battery device (10) includes a plurality of tabs (300), and the first welding portion (311) of the tab (300) is connected to the second welding portion (112) in a one-to-one correspondence. In the unfolded electrode (100), the length direction of the electrode (100) is consistent with the second direction.

13. The battery device according to claim 12, characterized in that, On the unfolded electrode (100), the dimension of the electrode (100) along its length direction is L, the number of tabs (300) is n, the distance between the tabs (300) near the edge of the electrode (100) along the length direction of the electrode (100) and the edge of the electrode (100) is f = (1 / 2n) × L; and multiple tabs (300) are evenly spaced along the length direction of the electrode (100); And / or, the dimension of the second weld portion (112) along the length direction of the unfolded electrode (100) is less than half the circumference of the second weld portion (112) at the ring where the second weld portion (112) is located after the electrode (100) is wound. And / or, the dimension of the widened portion (320) along the length direction of the unfolded electrode (100) is smaller than half the circumference of the second welded portion (112) corresponding to the widened portion (320) at the location of the ring after the electrode (100) is wound; And / or, on the unfolded electrode (100), the dimension of the first weld portion (311) along the length direction of the electrode (100) is 50%-85% of the dimension of the second weld portion (112) along the length direction of the electrode (100); And / or, the dimension of the tab body (310) along the first direction is 80%-120% of the dimension of the second welded part (112) along the first direction; And / or, the thickness of the first weld (311) is 30%-150% of the thickness of the active material layer (120).

14. The battery device according to any one of claims 8 to 13, characterized in that, It also includes a collector plate (200), and the widening portion (320) is connected to the collector plate (200); Alternatively, the tab (300) may further include an extension (330) connected to the side of the widened portion (320) away from the tab body (310) along the first direction, and the extension (330) is connected to the collector plate (200).

15. An electrical appliance, characterized in that, Includes the battery device (10) as described in any one of claims 8 to 14.

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