Battery and electric device

Abstract

The present application discloses a battery and an electric device. The battery comprises an outer casing, an electrode assembly, and an electrolyte; the electrode assembly is arranged in an internal space of the outer casing, and the internal space of the outer casing is filled with the electrolyte; the electrode assembly comprises electrode sheets, each electrode sheet comprises a main body portion and a plurality of protruding portions, and each protruding portion is formed by part of the electrode sheet protruding towards one side of the main body portion; the distance between the centers of two adjacent protruding portions is L, wherein 0.5 mm≤L≤4.0 mm; and the viscosity of the electrolyte at 25℃ is η, wherein 3.0≤η / L≤7.0. The distance between two adjacent protruding portions is matched with the viscosity of the electrolyte, the protruding portions can provide sufficient support for a separator, and the electrolyte can smoothly flow between the protruding portions, thereby achieving better electrolyte storage, improving the wetting effect of the electrolyte, preventing local electrolyte shortage, improving the ion transport effect between the electrode sheets and the separator, improving the charge and discharge cycle performance of the battery, improving the bonding between the electrode sheets and the separator, and improving the overall interface consistency of the battery.

Description

A battery and an electrical device

[0001] This application claims priority to Chinese Patent Application No. 202411515656.7, filed on October 28, 2024, entitled "A Battery and an Electric Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more particularly to a battery and an electrical device. Background Technology

[0003] Charge-discharge cycle life is a key performance indicator for batteries. In addition to optimizing and innovating the materials of the electrolyte and electrode sheets to improve charge-discharge cycle life, structural design and improvement of the battery's electrode components can also effectively contribute to improving charge-discharge cycle life. This places higher demands on the structural design of the electrode components. Summary of the Invention

[0004] The inventors discovered that there is compression between the layers of the electrode assembly. Especially during the charging and discharging process of the battery, the expansion and compression of the electrode assembly will be further aggravated, resulting in insufficient electrolyte between the layers of the electrode assembly, poor wetting, and easy interface deterioration, or even abnormal situations such as poor wetting and cycle failure.

[0005] This application provides a battery and an electrical device that can improve the problem of poor electrolyte wetting in batteries.

[0006] In a first aspect, embodiments of this application provide a battery, including an outer packaging, an electrode assembly, and an electrolyte. The electrode assembly is disposed within the internal space of the outer packaging, and the electrolyte fills the internal space of the outer packaging. The electrode assembly includes an electrode sheet, which includes a main body and a plurality of protrusions. The protrusions are formed by a portion of the electrode sheet protruding towards the thickness direction of the main body. The center-to-center distance between two adjacent protrusions is L (mm), where 0.5 ≤ L ≤ 4.0. The viscosity of the electrolyte at 25°C is η (MPa·s), where 3.0 ≤ η / L ≤ 7.0.

[0007] In some embodiments, the battery satisfies at least one of the following conditions:

[0008] (1) 1.2 ≤ L ≤ 3.5;

[0009] (3) 6 ≤ η / L ≤ 6.8;

[0010] (2) 6.0 ≤ η ≤ 14.0.

[0011] In some embodiments, the protrusion height of the outer surface of the protrusion is H (mm), and the diameter of the inscribed ball on the inner surface of the protrusion is R (mm), 9.38≤L2 / (2HR-H)2 )≤79.75.

[0012] In some embodiments, the battery satisfies at least one of the following conditions:

[0013] (1) 0.05 ≤ H ≤ 0.08;

[0014] (2) 0.3 ≤ R ≤ 2.0.

[0015] In some embodiments, the projected area of ​​the outer surface of the protrusion in the thickness direction of the electrode sheet is S (mm²). 2 The electrode must satisfy at least one of the following conditions:

[0016] (1) 0.16 ≤ S ≤ 2.0;

[0017] (2) 12.5 ≤ S / H ≤ 33.3.

[0018] The unit of S / H is mm.

[0019] In some embodiments, the electrode includes a current collector and an active material layer attached to the surface of the current collector. The tensile strength of the current collector is T (MPa), and the projected area of ​​the outer surface of the protrusion in the thickness direction of the electrode is S (mm²). 2 The electrode meets at least one of the following conditions:

[0020] (1) 30≤T≤400;

[0021] (2) 100≤T / S≤200.

[0022] The unit of T / S is MPa / mm. 2 .

[0023] In some embodiments, a plurality of protrusions are arranged side-by-side and spaced apart along a first direction of the electrode to form a group of protrusion units. In a second direction of the electrode, adjacent groups of protrusion units are spaced apart. The first direction, the second direction, and the thickness direction of the electrode are all perpendicular to each other. The distance between two adjacent protrusions in both the first and second directions satisfies the range L. The protrusions of two adjacent protrusion units are collinear in the second direction; or, one of the protrusion units is translated relative to the other protrusion unit by a predetermined distance A in the first direction, where A satisfies: 0.3L ≤ A ≤ L.

[0024] In some embodiments, in the thickness direction of the electrode sheet, all protrusions are bent toward the same side of the main body; or,

[0025] In the thickness direction of the electrode, one part of the protrusion bends toward one side of the main body, and the other part of the protrusion bends toward the other side of the main body.

[0026] In some embodiments, the electrolyte comprises linear ester compounds, wherein the weight percentage of the linear ester compounds is W based on the total mass of the electrolyte, 40 wt.% ≤ W ≤ 60 wt.%.

[0027] In some embodiments, the electrode assembly includes a positive electrode, a negative electrode, and a separator, the separator being disposed between the positive and negative electrode; at least one of the positive and negative electrode is formed by the electrode having a protrusion.

[0028] Secondly, embodiments of this application provide a battery, including an outer packaging and the aforementioned electrode assembly, wherein the electrode assembly is disposed within the internal space of the outer packaging.

[0029] Based on the battery and power device of this application embodiment, by selecting protrusions that satisfy the conditions 0.5≤L≤4.0 and 3.0≤η / L≤7.0, the spacing between two adjacent protrusions is matched with the viscosity of the electrolyte. The protrusions can provide sufficient support for the separator, and the electrolyte can flow smoothly between the protrusions, achieving better electrolyte storage, improving the wetting effect of the electrolyte, preventing local liquid shortage, improving the ion transport effect between the electrode and the separator, improving the charge and discharge cycle performance of the battery, and also improving the adhesion between the electrode and the separator, improving the overall interface consistency of the battery. Attached Figure Description

[0030] 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a front view of a schematic diagram of the electrode sheet in an unfolded state according to an embodiment of this application;

[0032] Figure 2 is a cross-sectional view of an electrode assembly according to an embodiment of this application;

[0033] Figure 3 is a partial cross-sectional view of an embodiment of the present application showing a electrode sheet with a protrusion.

[0034] Figure 4 is a front view schematic diagram of an embodiment of the present application of an electrode sheet having an end clearance area;

[0035] Figure 5 is a front view schematic diagram of the electrode sheet having an electrode tab region according to an embodiment of this application;

[0036] Figure 6 is a schematic diagram of the front view of the electrode tab region penetrating the electrode sheet according to an embodiment of this application.

[0037] Reference numerals: 20, Electrode body; 21, Straight section; 22, Corner section; 100, Electrode tab; 40, Electrode tab assembly; 50, Separating membrane; 300, Electrode sheet; 311, Protrusion; 3111, Inner surface; 3112, Outer surface; 312, Main body; 410, Positive electrode sheet; 420, Negative electrode sheet; 310, Protrusion area; 320, Electrode tab area; 321, Electrode tab mounting area; 322, Protective adhesive mounting area; 330, End clearance area; 3201, First side boundary; 3202, Second side boundary; 3203, Bottom boundary; 3204, Third side boundary; 3205, Fourth side boundary; 331, Head clearance area; 332, Tail clearance area; 3411, First edge; 3421, Second edge; 3431, Third edge; 3441, Fourth edge; 3101, First boundary; 3102, Second boundary; 3103, Third boundary; 3104, Fourth boundary; 341, First region; 342, Second region; X, Length direction; Y, Width direction; Z, Thickness direction. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] The inventors discovered that during battery charging and discharging, the electrode components expand, and the compression between the electrode component layers is further aggravated, resulting in insufficient electrolyte between the electrode component layers, poor wetting, easy interface deterioration, and even cycle failure.

[0040] The inventors also discovered that during the processing of electrode assemblies, the positive electrode, separator, and negative electrode are sequentially stacked and wound multiple times to form an electrode body with multiple winding units. By increasing the spacing between adjacent winding units and providing protrusions on the electrode to support adjacent winding units, the compression problem caused by electrode assembly expansion can be improved. However, the presence of protrusions will also interfere with the flow of electrolyte to some extent, thus affecting the electrolyte wetting effect. Based on this, embodiments of this application provide a battery and electrical device that design protrusions on the electrode to effectively improve electrolytic wetting and electrode interface problems.

[0041] The battery provided in this application includes an outer packaging and an electrode assembly disposed within the inner space of the outer packaging, as well as an electrolyte filling the inner space of the outer packaging. The electrode assembly includes two electrodes with opposite polarities and a separator. As shown in FIG1, which is a front view of an embodiment of the present application with the electrode 300 in an unfolded state, the electrode 300 has a length direction X, a width direction Y, and a thickness direction Z that are perpendicular to each other. The length direction X, width direction Y, and thickness direction Z of the two electrodes 300 with opposite polarities of the electrode assembly are consistent. The separator 50 is disposed between the two electrodes 300 with opposite polarities in the thickness direction Z of the electrode 300. One of the two electrodes 300 with opposite polarities is a positive electrode 410 and the other is a negative electrode 420. The separator 50 has insulating properties to separate the positive electrode 410 and the negative electrode 420 to prevent the positive electrode 410 and the negative electrode 420 from short-circuiting.

[0042] As shown in Figure 2, the separator 50 and two electrode sheets 300 are wound multiple times along the length direction X of the electrode sheets 300 to form the electrode body 20. The length direction X of the electrode sheets 300 is the direction in which the electrode sheets 300 are wound. The electrode body 20 is flat. Each turn of the electrode sheet 300 includes two straight sections 21 and two corner sections 22. The two straight sections 21 are arranged opposite each other in a direction perpendicular to the surface of the straight sections 21. The two straight sections 21 are arranged between the two corner sections 22 in a direction parallel to the surface of the straight sections 21. The two straight sections 21 and the two corner sections 22 are connected end to end. Among them, the corner sections 22 of adjacent turns of the electrode sheet 300 are prone to mutual compression, the straight sections 21 of adjacent turns of the electrode sheet 300 are also prone to mutual compression, and there is also compression between the straight sections 21 and corner sections 22 of the same turn of the electrode sheet 300. Therefore, these compressed areas are prone to insufficient electrolyte wetting.

[0043] In this embodiment, the electrode 300 includes a main body 312 and a plurality of protrusions 311. Each protrusion 311 is formed by a portion of the electrode 300 protruding toward one side of the main body 312, that is, each protrusion 311 protrudes in the thickness direction Z of the electrode 300. The electrode 300 includes a first surface perpendicular to the thickness direction Z of the electrode 300. Referring again to FIG1, the first surface includes a protrusion area 310, and the plurality of protrusions 311 are disposed in the protrusion area 310. There is a gap between the protrusion area 310 and the edge of the first surface. After the two electrodes 300 and the separator 50 are wound multiple times to form the electrode body 20, the protrusion 311 contacts the separator 50 to provide support for the separator 50. When the electrode body 20 expands, the protrusion 311 can still support the separator 50. The small contact area between the protrusion 311 and the separator 50 allows space between the part of the electrode 300 corresponding to the protrusion area 310 and the separator 50 to accommodate the electrolyte, preventing abnormal situations such as insufficient electrolyte or poor wetting between the electrode 300 and the separator 50 due to expansion and compression.

[0044] Both the straight section 21 and the corner section 22 have protrusions 311 to support the separator 50 of the corresponding straight section 21 and corner section 22. Optionally, all the protrusions 311 provided on a single electrode 300 protrude in the same direction toward the electrode 300 in the thickness direction Z of the electrode 300. For example, the protrusions 311 provided on the straight section 21 protrude toward the side where the electrode body 20 is wound, and the protrusions 311 provided on the corner section 22 protrude toward the side where the electrode body 20 is wound; or, the protrusions 311 provided on the straight section 21 protrude toward the side away from the winding center of the electrode body 20, and the protrusions 311 provided on the corner section 22 protrude toward the side away from the winding center of the electrode body 20. Optionally, a portion of the protrusions 311 on a single electrode 300 protrude toward one side of the electrode 300 in the thickness direction Z, and another portion of the protrusions 311 protrude toward the other side of the electrode 300 in the thickness direction Z. For example, the protrusions 311 on the straight section 21 protrude toward the side facing the winding center of the electrode body 20, and the protrusions 311 on the corner section 22 protrude toward the side away from the winding center of the electrode body 20; or, the protrusions 311 on the straight section 21 protrude toward the side away from the winding center of the electrode body 20, and the protrusions 311 on the corner section 22 protrude toward the side facing the winding center of the electrode body 20.

[0045] The above is merely an illustrative description. This application does not limit the orientation of the protrusions 311 of each electrode 300, and the orientation can be selected according to actual needs.

[0046] In this embodiment of the application, the viscosity of the electrolyte at 25°C is η, as shown in Figure 3. The center-to-center distance between two adjacent protrusions 311 is L, where 0.5≤L≤4.0 and 3.0≤η / L≤7.0. For example, L can be 0.5mm, 0.8mm, 1.5mm, 2.0mm, 2.7mm, 3.2mm, 4.0mm or any range thereof, and η / L can be 3.0, 3.5, 4.2, 4.6, 5.3, 6.2, 7.0 or any range thereof. By selecting the range where the protrusions 311 and the electrolyte satisfy the above-mentioned conditions, the spacing between two adjacent protrusions 311 and the viscosity η of the electrolyte are matched. The protrusions 311 can provide sufficient support for the separator 50, and the electrolyte can flow smoothly between the protrusions 311, achieving better electrolyte storage, improving the wetting effect of the electrolyte, preventing local electrolyte shortage, improving the ion transport effect between the electrode 300 and the separator 50, improving the charge-discharge cycle performance of the battery, and also improving the adhesion between the electrode and the separator, improving the overall interface consistency of the battery. When L is higher than the upper limit of 4.0 mm, the spacing between two adjacent protrusions 311 is too large, the support capacity of the protrusions 311 is insufficient, the improvement of the electrolyte wetting effect is limited, and it is also easy to cause poor adhesion between the electrode and the separator, deterioration of the interlayer interface consistency, and deterioration of the battery's self-discharge performance. When L is lower than the lower limit of 0.5 mm, the spacing between two adjacent protrusions 311 is too small, which is easy to cause insufficient space between two adjacent protrusions 311, resulting in insufficient electrolyte storage capacity. When η / L is higher than the upper limit, the electrolyte viscosity is too high, making it difficult for the electrolyte to flow and reducing its wetting effect. This leads to poor charge-discharge cycle performance and can also cause purple spots or lithium plating during cycling. When η / L is lower than the lower limit, the distance between two adjacent protrusions 311 is too large, resulting in insufficient support capacity of the protrusions 311 and a poor effect on improving the charge-discharge cycle performance of the battery.

[0047] In some embodiments, the electrolyte satisfies the following viscosity range: 6.0 ≤ η ≤ 14.0. For example, η can be 6.0 mPa·s, 8.5 mPa·s, 9.8 mPa·s, 10.2 mPa·s, 11.5 mPa·s, 14.0 mPa·s, or any range thereof. Within this viscosity range, the electrolyte can flow smoothly through the gap between the electrode 300 and the separator 50, improving the wetting effect of the electrolyte, enhancing the kinetic performance of the battery, and increasing the lithium-ion transport efficiency.

[0048] In some embodiments, the electrolyte comprises a linear ester compound, wherein the weight percentage (W) of the linear ester compound is 40 wt.% ≤ W ≤ 60 wt.% based on the total mass of the electrolyte. For example, W can be 40 wt.%, 45 wt.%, 48 wt.%, 51 wt.%, 55 wt.%, 60 wt.%, or any range thereof. Within this range, it is convenient to control the viscosity of the electrolyte within a suitable range, preventing excessively high electrolyte viscosity from reducing the wetting effect of the electrolyte, and preventing excessively low electrolyte viscosity from leading to insufficient battery system kinetics and lithium plating during cycling.

[0049] In some embodiments, the linear ester compounds of this application include at least one of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, and methyl butyl carbonate.

[0050] As shown in Figure 3, the protrusion 311 has an inner surface 3111 connected to one surface of the main body 312 and an outer surface 3112 connected to the other surface of the main body 312. The outer surface 3112 of the protrusion 311 has a vertex Q and a base m. The base m of the protrusion 311 is connected to the surface of the main body 312 of the electrode 300. The protrusion 311 protrudes from the main body 312 of the electrode 300. The vertex Q of the protrusion 311 is the point on the protrusion 311 that is furthest from the base m in the thickness direction Z of the electrode 300. The protrusion height H of the outer surface 3112 is the dimension from the vertex Q to the base m of the protrusion 311 in the thickness direction Z of the electrode 300. The protrusion 311 has a central axis K passing through the vertex Q and parallel to the thickness direction of the electrode 300. The center distance L between two adjacent protrusions 311 is the distance between the central axes K of the two adjacent protrusions 311 in the direction perpendicular to the thickness direction Z of the electrode 300.

[0051] The top surface of the outer surface 3112 of the protrusion 311 that contacts the separator 50 is an arc surface to prevent the tip of the protrusion 311 from being too sharp and piercing the separator 50. The outer surface 3112 of the protrusion 311 has a similar shape to the inner surface 3111. The top surface of the outer surface 3112, which is an arc surface, is located inscribed in sphere D1. The part of the inner surface 3111 of the protrusion 311 corresponding to the top surface of the outer surface 3112 is also an arc surface, and this arc surface is located inscribed in sphere D2. Inscribed in spheres D1 and D2 share the same center, and the diameter of the inscribed in sphere D2 of the inner surface 3111 of the protrusion 311 is R.

[0052] Where, 9.38≤L2 / (2HR-H) 2 )≤105, for example, L 2 / (2HR-H 2The value can be 9.38, 10.5, 15.0, 22.3, 55.0, 47.8, 86.3, 94.0, 79.75, 105.0, or any range of both. By selecting a range where the protrusions 311 satisfy the above conditions, the distribution density of the protrusions 311 per unit area of ​​the electrode 300 can be controlled appropriately, facilitating smooth flow of the electrode 300 between the protrusions 311. This also allows for better electrolyte storage, improved electrolyte wetting, and improved ion transport between the electrode 300 and the separator 50. Furthermore, by ensuring the height, spacing, and sharpness of the protrusions 311 are within a suitable range, the protrusions 311 possess good structural strength, are not easily deformed, provide more stable support for the separator 50, and are less likely to puncture the separator 50. They also improve electrode elongation, giving the electrode suitable elongation. When L... 2 / (2HR-H 2 ) higher than the upper limit of 105.0, or when L 2 / (2HR-H 2 When the concentration exceeds the upper limit of 79.75, the distribution density of the protrusions 311 is too sparse, and the protrusion degree of the protrusions 311 is insufficient. This can easily lead to insufficient support force of the protrusions 311, and can also easily cause the electrode sheet to deteriorate in its XY direction (i.e., the length and width directions) during circulation, puncturing the separator or outer packaging and other structures. When L 2 / (2HR-H 2 If the density of the protrusions 311 is too high below the lower limit of 4.0, it may lead to an excessively small gap between the electrode 300 and the separator 50, resulting in poor electrolyte wetting effect and making it easy for the battery to develop dotted purple spots or lithium plating corresponding to the distribution of the protrusions during cycling.

[0053] In some embodiments, the electrode 300 satisfies: 0.05 ≤ H ≤ 0.08, where H can be 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, or any range thereof. Within the above spacing range, the gap between the electrode 300 and the separator 50 is better, resulting in better electrolyte wetting. When H is higher than the upper limit of 0.08 mm, the height of the protrusion 311 is too high, making it prone to deformation. When H is lower than the lower limit of 0.02 mm, the height of the protrusion 311 is too low, resulting in insufficient support for the separator 50. The gap between the electrode 300 and the separator 50 is too small, leading to poor improvement in electrolyte wetting.

[0054] In some embodiments, the electrode 300 satisfies: 0.3 ≤ R ≤ 2.0. For example, R can be 0.3 mm, 0.6 mm, 0.9 mm, 1.3 mm, 1.5 mm, 2.0 mm, or any range thereof. Within the above radius range, the protrusion of the electrode 300 is appropriate, preventing the protrusion 311 from easily deforming under external forces. The protrusion 311 has good supporting structural strength, which facilitates matching with the height H of the protrusion 311, making the area occupied by the protrusion 311 of the entire electrode 300 appropriate. Consequently, the distribution density of the protrusion 311 within a unit area is appropriate, and it can also play a role in storing residual electrolyte, improving the electrolyte retention capacity of the battery.

[0055] In some embodiments, the projected area of ​​the outer surface 3112 of the protrusion 311 in the thickness direction Z of the electrode 300 is S, where 0.16 ≤ S ≤ 2.0, for example, S can be 0.16 mm. 2 0.18mm 2 0.20mm 2 0.80mm 2 1.22mm 2 1.64mm 2 2.00mm 2 Or any range of the two mentioned above. By selecting the projected area of ​​the protrusion 311 to meet the above range, it is easy to control the space occupied by the protrusion 311 appropriately, so that there is a suitable space between the separator 50 and the main body 312 of the electrode 300 for accommodating the electrolyte, and it can also enhance the rigidity of the substrate and prevent the substrate from wrinkling and bending.

[0056] In some embodiments, 12.5 ≤ S / H ≤ 33.3, for example, S / H can be 12.5 mm, 15.0 mm, 23.5 mm, 28.0 mm, 33.3 mm, or any range thereof. By selecting the ratio of the projected area S and height H of the protrusion 311 to be within the above range, the protrusion 311 is smoother, preventing the connection between the protrusion 311 and the main body 312 from being too steep, which would make the protrusion 311 susceptible to deformation under external forces. This greatly improves the self-discharge performance of the battery, helps to improve the charge-discharge cycle performance of the battery, extends its service life, and also reduces stress concentration during battery cycling, thus improving the battery expansion problem.

[0057] In some embodiments, the electrode 300 includes a current collector and an active material layer connected to the surface of the current collector; the tensile strength of the current collector is T, 100≤T / S≤200, for example, T / S can be 100MPa / mm. 2 110MPa / mm 2 120MPa / mm 2 130MPa / mm 2150MPa / mm 2 180MPa / mm 2 200MPa / mm 2 Or any range of the two mentioned above. By selecting the tensile strength T of the current collector and the projected area S of the protrusion 311 to be within a suitable range, the electrode 300 is not easily deformed or damaged, and can maintain the shape of the protrusion 311 when subjected to a large force, thus improving the self-discharge performance of the battery. At the same time, during the charging and discharging process, under the influence of the expansion force, the ductility of the electrode 300 is suitable, which can significantly improve the charge and discharge cycle performance of the battery, and can also prevent the electrode from puncturing the separator or the outer packaging, thus preventing electrolyte leakage and safety risks.

[0058] In some embodiments, 30≤T≤400 can prevent deformation or breakage due to insufficient strength during the manufacturing and use of the electrode 300. It also makes it easier to control the process during the manufacturing of the electrode 300, reduces manufacturing defects, improves mechanical strength and electrochemical stability, improves the overall durability of the battery, and can also improve production efficiency and reduce production costs.

[0059] In some embodiments, a plurality of protrusions 311 are arranged side-by-side and spaced apart along a first direction of the electrode 300 to form a group of protrusion units. In a second direction of the electrode 300, adjacent groups of protrusion units are spaced apart. The first direction, the second direction, and the thickness direction Z of the electrode 300 are mutually perpendicular. Optionally, the first direction is the length direction X of the electrode 300 and the second direction is the width direction Y of the electrode 300, or the first direction is the width direction Y of the electrode 300 and the second direction is the length direction X of the electrode 300. As shown in Figures 1 and 4, the distance between two adjacent protrusions 311 in both the first and second directions satisfies the range L. As shown in Figure 1, the protrusions 311 of two adjacent protrusion units are collinear in the second direction; or, as shown in Figure 4, one protrusion unit is translated relative to the other protrusion unit by a preset distance A in the first direction, where A satisfies: 0.3L ≤ A ≤ L. In the above arrangement, the orderly arrangement of the protrusions 311 helps the electrolyte to wet and the ion to transfer, while providing uniform support. During the charging and discharging process, it can provide good support stability and improve the charge and discharge cycle performance of the battery. The orderly arrangement of the protrusions 311 can also reduce the bubbles in the electrolyte, improve the uniformity of electrolyte transport, and increase the conductivity of the electrode, thereby reducing the internal resistance of the battery.

[0060] In some embodiments, the electrode 300 has one active material layer, disposed along the thickness direction Z of the electrode 300 on one surface of the current collector; or, the electrode 300 has two active material layers, disposed along the thickness direction Z of the electrode 300, with one active material layer disposed on one surface of the current collector and the other active material layer disposed on the other surface of the current collector. The thickness of the current collector is h1, 0.001 ≤ h1 ≤ 0.200, and the thickness of the active material layer is h2, 0.010 ≤ h2 ≤ 0.500. In this embodiment, the protrusion 311 is formed by a portion of the current collector and a portion of the active material layer. For example, the protrusion 311 in this embodiment can be processed by rolling. Specifically, a roll acts on one side of the electrode 300 on a portion of the electrode 300, causing the current collector and the active material layer in that region to deform and bend together, thus forming the protrusion 311.

[0061] In some embodiments, the surface of the active material layer facing away from the current collector forms a first surface. The first surface includes a bump region 310, and a protrusion 311 is disposed in the bump region 310. The bump region 310 is defined by a bump boundary line. The protrusion 311 of the bump region 310 may be located in the inner region defined by the bump boundary line, or the protrusion 311 may be internally connected to the bump boundary line. The first surface also includes an end clearance region 330 and an edge clearance region. The end clearance region 330 is connected to the end of the bump region 310 in the length direction X of the electrode 300 and extends to the edge of the electrode 300. The edge clearance region is disposed on one side of the bump region 310 in the width direction Y of the electrode 300 and extends to the edge of the electrode 300. Neither the edge clearance region nor the end clearance region 330 is provided with a protrusion 311. After the two electrodes 300 and the separator 50 are wound together, the surfaces of the electrodes 300 corresponding to the edge clearance region and the end clearance region 330 may be spaced apart from the separator 50.

[0062] The end clearance area 330 is located at the end of the protrusion area 310 in the length direction X of the electrode 300 and extends to the edge of the electrode 300. The end clearance area 330 also extends to the edge of the electrode 300 in the width direction Y of the electrode 300. As shown in FIG4, the end clearance area 330 includes at least one of the head clearance area 331 and the tail clearance area 332. Preferably, the end clearance area 330 includes both the head clearance area 331 and the tail clearance area 332. In the length direction X of the electrode 300, the head clearance area 331 is located at one end of the protrusion area 310 and the tail clearance area 332 is located at the other end of the protrusion area 310.

[0063] After the two electrodes 300 and the separator 50 are wound, the head clearance area 331 can be located in the innermost few turns of the electrode body 20, which facilitates the winding and forming of the electrode body 20 and helps to improve the structural stability of the central area of ​​the electrode body 20. The tail clearance area 332 can be located in the outermost few turns of the electrode body 20. The tail clearance area 332 can serve as a buffer area between the protrusion 311 and the tail end of the electrode body 20, so that the portion of the clearance area 330 at the corresponding end of the electrode 300 can more smoothly bind the inner layer structure of the electrode body 20, which helps to improve the encapsulation stability of the electrode body 20. Especially when the electrode body 20 has a tendency to expand, using the tail clearance area 332 without the protrusion 311 to finish can prevent the tail end of the electrode body 20 from slipping due to expansion stress, thereby improving the structural stability of the electrode body 20.

[0064] Specifically, the first surface of the electrode 300 includes a first edge 3411 and a second edge 3421 disposed opposite to each other in the length direction X of the electrode 300, and the convex boundary line of the convex region 310 includes a first boundary 3101 and a second boundary 3102 disposed opposite to each other in the length direction X of the electrode 300, with the first boundary 3101 corresponding to the first edge 3411 and the second boundary 3102 corresponding to the second edge 3421. The head clearance area 331 is formed between the first edge 3411 and the first boundary 3101, and the tail clearance area 332 is formed between the second edge 3421 and the second boundary 3102. One end of the separator 50 is flush with or extends out of the head clearance area 331 to be sandwiched between two electrodes 300 with opposite polarities. The electrode 300 is wound from the head clearance area 331 and the separator 50 along the length direction X of the electrode 300 to form a flat electrode body 20. That is, the head clearance area 331 is located in the inner circle of the electrode body 20, and the tail clearance area 332 is located in the outer circle of the electrode body 20. The other end of the separator 50 extends out of the tail clearance area 332 in the winding direction of the electrode 300 to prevent the separator 50 from shrinking and causing the two electrodes 300 with opposite polarities to short-circuit.

[0065] The first surface of the electrode 300 has an edge clearance area, which includes a first region 341 and a second region 342. In the width direction Y of the electrode 300, the first region 341 is connected to one side of the protrusion region 310, and the second region 342 is connected to the other side of the protrusion region 310. The first region 341 extends to the edge of the electrode 300 in a direction away from the second region 342, and the second region 342 extends to the edge of the electrode 300 in a direction away from the first region 341. That is, the two opposite boundaries of the protrusion region 310 in the width direction Y of the electrode 300 are respectively spaced from the corresponding edge of the electrode 300, so as to prevent the deformation stress when the protrusion 311 is processed in the protrusion region 310 from causing abnormal deformation such as wavy edges or wrinkles on the edge of the electrode 300.

[0066] Specifically, the electrode 300 includes a third edge 3431 and a fourth edge 3441 disposed opposite to each other in the width direction Y of the electrode 300. The convex boundary line of the convex region 310 includes a third boundary 3103 and a fourth boundary 3104 disposed opposite to each other in the width direction Y of the electrode 300. The third boundary 3103 corresponds to the third edge 3431, and the fourth boundary 3104 corresponds to the fourth edge 3441. A first region 341 is formed between the third boundary 3103 and the third edge 3431, and a second region 342 is formed between the fourth boundary 3104 and the fourth edge 3441. The first region 341 and the second region 342 extend in the length direction X of the electrode 300 to connect with the end clearance region 330. That is, the extension line of the first boundary 3101, the extension line of the second boundary 3102, the third boundary 3103 and the fourth edge 3441 are connected to the end clearance region 330. The first region 341 is defined by three edges 3431. The extension of the first boundary 3101, the extension of the second boundary 3102, the fourth boundary 3104 and the fourth edge 3441 define the second region 342. The extension of the first boundary 3101, the first edge 3411, the third edge 3431 and the fourth edge 3441 define the head clearance zone 331. The extension of the second boundary 3102, the second edge 3421, the third edge 3431 and the fourth edge 3441 define the tail clearance zone 332. The protrusion area 310 is located in the region defined by the first boundary 3101, the second boundary 3102, the third boundary 3103 and the fourth boundary 3104. The protrusion 311 can be internally connected to at least one of the first boundary 3101, the second boundary 3102, the third boundary 3103 and the fourth boundary 3104.

[0067] Optionally, the first boundary 3101, the second boundary 3102, the first edge 3411 and the second edge 3421 are parallel to the width direction Y of the electrode 300, and the third boundary 3103, the fourth boundary 3104, the third edge 3431 and the fourth edge 3441 are parallel to the length direction X of the electrode 300. In this case, the head clearance area 331 and the tail clearance area 332 are each independently rectangular or square, and the first region 341 and the second region 342 are rectangular.

[0068] Optionally, one of the first region 341 and the second region 342 is used to mount the electrode assembly tab 40. As shown in FIG4, exemplaryly, the second region 342 is used to mount the electrode assembly tab 40, and the protrusion region 310 is spaced apart from the tab assembly 40. In this case, the protrusion region 310 is defined by the first boundary 3101, the second boundary 3102, the third boundary 3103, and the fourth boundary 3104.

[0069] Optionally, as shown in FIG5, the first surface further includes a tab region 320, which extends from the third boundary 3103 toward the side where the fourth boundary 3104 is located. The tab region 320 is used to install the tab assembly 40 for mounting the electrode assembly, and the tab assembly 40 is spaced apart from the protrusion region 310. When mounting the tab assembly 40 onto the tab region 320, the processing method affects the mounting stability of the tab assembly 40 and the stability of the surrounding structure, which in turn affects the stability of the electrode 300 interface. For example, when the tab assembly 40 is pressed onto the electrode 300 using a roll forming method, the tab assembly 40 may be pressed together with the area where the protrusion 311 is located, or the distance between the tab assembly 40 and the protrusion 311 may be too close, which may result in deformation of the protrusion 311 or indentation. By planning the tab region 320 for mounting the tab assembly 40, the installation of the tab assembly 40 is facilitated, the process difficulty is reduced, the mounting stability of the tab assembly 40 is improved, and the interface stability near the tab assembly 40 is improved. It can also make the tab assembly 40 and the protrusion 311 misaligned in the thickness direction Z of the electrode 300, which helps to improve the energy density of the battery when the electrode assembly is used in the battery.

[0070] Each tab region 320 is used to provide at least one tab assembly 40. For example, the tab assembly 40 includes a tab and a protective adhesive, and the tab and the protective adhesive can be installed in the same tab region 320; or, the tab is installed in one tab region 320 and the protective adhesive is installed in another tab region 320.

[0071] There are multiple tabs, some of which are installed on one electrode plate 300 and others on another electrode plate 300. The tabs installed on the positive electrode plate 410 are positive tabs, and the tabs installed on the negative electrode plate 420 are negative tabs. The tab area 320 includes a tab mounting area for mounting the tabs of the electrode assembly.

[0072] Optionally, as shown in Figure 5, the tab region 320 extends from the fourth boundary 3104 along the width direction Y of the electrode 300 to the side where the third boundary 3103 is located, and is spaced apart from the third boundary 3103; or, as shown in Figure 6, the tab region 320 extends from the fourth boundary 3104 along the width direction Y of the electrode 300 through the protrusion region 310.

[0073] The electrode 300 includes a positive electrode 410 and a negative electrode 420. In this application embodiment, there are no special restrictions on the materials of the positive electrode 410 and the negative electrode 420. Various materials known in the art that can be used as the positive electrode 410 and the negative electrode 420 are applicable to this application.

[0074] Exemplarily, the negative electrode current collector can be at least one of copper foil, aluminum foil, nickel foil, or carbon-based current collector; the thickness of the negative electrode current collector can be from 1 μm to 200 μm. The negative electrode active material layer can be disposed on one or both opposing surfaces of the negative electrode current collector. Further, in the thickness direction Z of the negative electrode sheet 420, the negative electrode active material layer can be coated only on a portion of the negative electrode current collector. Exemplarily, the thickness of the negative electrode active material layer can be from 10 μm to 500 μm.

[0075] The negative electrode active material layer includes a negative electrode active material. Exemplarily, the negative electrode active material includes at least one of lithium metal, natural graphite, artificial graphite, or a silicon-based material. The silicon-based material includes at least one of silicon, silicon oxides, silicon carbide compounds, or silicon alloys. The negative electrode active material layer may also include a conductive agent and / or a binder. Exemplarily, the conductive agent in the negative electrode active material layer may include at least one of carbon black, acetylene black, Ketjen black, sheet graphite, graphene, carbon nanotubes, carbon fibers, or carbon nanowires; the binder in the negative electrode active material layer may include at least one of carboxymethyl cellulose (CMC), polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyaniline, polyimide, polyamide-imide, polysiloxane, styrene-butadiene rubber, epoxy resin, polyester resin, polyurethane resin, or polyfluorene.

[0076] In some exemplary embodiments, the positive electrode 410 includes a positive current collector and a positive active material layer disposed on the surface of the positive current collector. Exemplarily, the positive current collector can be aluminum foil; however, other positive current collectors commonly used in the art can also be used, and the thickness of the positive current collector can be from 1 μm to 200 μm. The positive active material layer can be disposed on one or both opposing surfaces of the positive current collector. Further, in the thickness direction Z of the positive electrode 410, the positive active material layer can be coated only on a portion of the positive current collector, and the thickness of the positive active material layer can be from 10 μm to 500 μm.

[0077] The positive electrode active material layer includes a positive electrode active material, exemplarily including LiCoO2, LiNiO2, LiMn2O4, and LiCo. 1-y M y O2, LiNi 1-y M y O2, LiMn 2-y M y O4, LiNi x Co y Mn z M 1-x-y-zO2, wherein M is selected from at least one of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, or Ti, and 0≤y≤1, 0≤x≤1, 0≤z≤1, x+y+z≤1. Exemplarily, the positive electrode active material may include at least one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or lithium nickel manganese oxide, and the above positive electrode active materials may be doped and / or coated. The positive electrode active material layer also includes a binder and a conductive agent. For example, the binder in the positive electrode active material layer may include at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, a styrene-acrylate copolymer, a styrene-butadiene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, or polyhexafluoropropylene; the conductive agent in the positive electrode active material layer may include at least one of conductive carbon black, acetylene black, Ketjen black, sheet graphite, graphene, carbon nanotubes, or carbon fibers.

[0078] The embodiments of this application do not have any particular limitations on the materials of the separator 50, the tabs, and the protective adhesive. Various materials known in the art that can be used as separator 50, tabs, and protective adhesives are applicable to this application.

[0079] Exemplarily, the separator 50 comprises at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid. For example, polyethylene includes at least one selected from high-density polyethylene, low-density polyethylene, or ultra-high molecular weight polyethylene. Polyethylene and polypropylene, in particular, are effective in preventing short circuits and can improve the stability of the electrode assembly through a turn-off effect. The thickness of the separator 50 is in the range of about 3 μm to 500 μm. The positive and negative tabs are made of a metallic conductive material.

[0080] This application does not impose any particular limitation on the electrolyte. Various materials known in the art that can be used as electrolytes are applicable to this application. Electrolytes include lithium salts and non-aqueous organic solvents.

[0081] For example, lithium salts include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium nitrate, and lithium methyl sulfite.

[0082] By way of example, the non-aqueous organic solvent may also contain at least one of a carboxylic acid ester compound, an ether compound, or other organic solvent. The aforementioned carbonate compound may include, but is not limited to, at least one of a chain carbonate compound and a cyclic carbonate compound. The aforementioned chain carbonate compound may include, but is not limited to, at least one of dipropyl carbonate (DPC) or ethyl methyl carbonate (EMC). The aforementioned cyclic carbonate compound may include, but is not limited to, at least one of butyl carbonate (BC) or vinyl ethylene carbonate (VEC). The aforementioned carboxylic acid ester compound may include, but is not limited to, at least one of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, or propyl propionate. The aforementioned ether compound may include, but is not limited to, at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane, 2-methyltetrahydrofuran, or tetrahydrofuran. The other organic solvents mentioned above may include, but are not limited to, at least one of dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolium ketone, N-methyl-2-pyrrolidone, formamide, dimethylformamide, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, or phosphate esters. This application does not impose any particular limitation on the mass percentage of non-aqueous organic solvents in the electrolyte, as long as the purpose of this application is achieved. For example, based on the total mass of the electrolyte, the mass percentage of non-aqueous organic solvents may be from 10% to 70%.

[0083] This application does not impose any particular restrictions on the packaging bag; it can be any packaging bag known in the art, as long as it can achieve the purpose of this application.

[0084] This application does not impose any particular limitation on the type of battery, which may include any device in which an electrochemical reaction occurs. In this application, the battery may include, but is not limited to: lithium metal battery, lithium-ion battery, lithium polymer battery, or lithium-ion polymer battery.

[0085] The battery manufacturing process described in this application is well known to those skilled in the art, and this application does not impose any particular limitations. For example, it may include, but is not limited to, the following steps: stacking the positive electrode, separator, and negative electrode in sequence, and performing operations such as winding and folding as needed to obtain a wound electrode assembly; placing the electrode assembly in a packaging bag; injecting electrolyte into the packaging bag and sealing it to obtain a battery; or stacking the positive electrode, separator, and negative electrode in sequence, and then fixing the four corners of the entire stacked structure with tape to obtain a stacked electrode assembly; placing the electrode assembly in a packaging bag; injecting electrolyte into the packaging bag and sealing it to obtain a battery. In addition, overcurrent protection components, conductive plates, etc., may be placed in the packaging bag as needed to prevent the internal pressure of the battery from rising and overcharging / discharging.

[0086] This application also provides an electrical device that includes the battery from any of the foregoing embodiments. Therefore, the electrical device provided by this application has excellent performance.

[0087] This application does not specifically limit the type of electrical device; it can be any electrical device known in the prior art. In some embodiments, the electrical device may include, but is not limited to, laptops, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0088] The present application will be further illustrated below using an electrode assembly of a lithium-ion battery as an example and in conjunction with specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0089] The performance of lithium-ion batteries in the embodiments and comparative examples of this application is tested using the following methods:

[0090] (1) Cyclic test at 25℃ / 45℃

[0091] In an environment of 25℃ / 45℃, the electrode assembly was charged to full charge voltage (battery design maximum voltage 4.5V) at a charging current of 1C, and then charged at the maximum voltage at a constant voltage until the current reached 0.02C. Then, it was discharged at a constant current at a discharge current of 0.7C until the final voltage reached 3.0V. The discharge capacity of the first cycle was recorded. The above steps were then repeated for 1000 charge-discharge cycles, and the discharge capacity of the lithium-ion battery after 1000 charge-discharge cycles was recorded.

[0092] The cycle capacity retention rate at 25℃ with 1C charging and 0.7C discharging is calculated as (discharge capacity of the 1000th cycle / discharge capacity of the first cycle) × 100%.

[0093] The cycle capacity retention rate at 45℃ with 1C charging and 0.7C discharging is calculated as (discharge capacity of the 800th cycle / discharge capacity of the first cycle) × 100%.

[0094] (2) Tensile strength test method for current collector

[0095] Prepare specimens according to standards (such as ASTM D882, ISO 527), obtaining specimens with dimensions of 150mm long × 10mm wide, and the thickness depending on the actual thickness of the current collector. Prepare multiple specimens (at least 5), placing them vertically (i.e., the surface of the current collector plate is parallel to the vertical direction). Clamp the upper and lower clamps of the universal testing machine at the edge of the specimen, with the clamps aligned along the length of the current collector, and each clamp width is 5mm, ensuring the specimen is aligned and not skewed within the clamps. Adjust the clamping force to ensure the specimen does not slip or get damaged. Set the tensile speed to 50mm / min, select the tensile test mode, start the testing machine, apply the tensile force, and record the force-displacement curve until the specimen breaks. Record the maximum tensile force, and take the average of the maximum tensile forces of multiple specimens; this is the tensile strength.

[0096] (3) Liquid retention test method

[0097] During the assembly of lithium-ion batteries, after drying in a vacuum oven at 85°C for 12 hours to remove moisture, the weight of the dry cell before liquid injection is recorded as w1. After vacuum sealing, settling, formation, capacity testing, degassing, and edge trimming, the weight of the lithium-ion battery is recorded as w2.

[0098] Liquid retention capacity = (w2-w1) / w1×100%.

[0099] (4) Test method for improving the effect of infiltration

[0100] Cut the electrode sheets to a standard size of 10mm × 10mm, ensuring the electrode surface is clean and free of contaminants. Observe the diffusion rate and wetting area of ​​the electrolyte by adding 5μL of electrolyte to the electrode surface. Measure the contact angle of the electrolyte on the electrode surface using a contact angle meter. Evaluate the wettability of the electrode based on the electrolyte diffusion rate and contact angle. A faster diffusion rate and a smaller contact angle indicate better wettability.

[0101] Among them, a contact angle range of 15° to 25° indicates "good" surface wetting effect, while a contact angle range of 5° to 15° indicates "poor" surface wetting effect.

[0102] Example 1-1

[0103] (1) Preparation of positive electrode sheet

[0104] Lithium cobalt oxide (LiCoO2) as the positive electrode active material, conductive carbon black as the conductive agent, and polyvinylidene fluoride (PVDF) as the binder were mixed at a mass ratio of 97.9:0.9:1.2. N-methylpyrrolidone (NMP) was added as a solvent, and the mixture was stirred evenly under vacuum to obtain a positive electrode slurry with a solid content of 75 wt%. The positive electrode slurry was uniformly coated onto one surface of a 9 μm thick aluminum foil used as a positive electrode current collector. The foil was then dried at 85°C and cold-pressed to obtain a positive electrode sheet with a single-sided coating thickness of 95 μm. The above steps were then repeated on the other surface of the aluminum foil to obtain a positive electrode sheet with a double-sided coating. After cutting, positive electrode sheets with dimensions of 74 mm × 851 mm were obtained for later use. The compaction density of the positive electrode material layer was 4.20 g / cm³. 3 .

[0105] (2) Preparation of negative electrode sheet

[0106] Artificial graphite (negative electrode active material), styrene-butadiene rubber (SBR) binder, and sodium carboxymethyl cellulose (CMC) thickener were mixed at a mass ratio of 97.4:1.4:1.2. Deionized water was then added as a solvent, and the mixture was stirred evenly under vacuum to obtain a negative electrode slurry with a solid content of 50 wt%. This negative electrode slurry was uniformly coated onto one surface of a 10 μm thick copper foil current collector. The foil was then dried at 85°C and cold-pressed to obtain a negative electrode sheet with a single-sided coating thickness of 130 μm. The above steps were repeated on the other surface of the same copper foil to obtain a negative electrode sheet with a double-sided coating. After cutting and welding of the negative electrode nickel tabs, a negative electrode sheet with dimensions of 76 mm × 867 mm was obtained for later use. The compaction density of the negative electrode material layer was 1.80 g / cm³. 3 .

[0107] (3) Preparation of the separating membrane

[0108] A porous polyethylene (PE) membrane with a thickness of 5 μm was used.

[0109] (4) Preparation of electrolyte

[0110] In an argon-atmospheric glove box with a water content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were mixed in a mass ratio of 1:1:2 to obtain a base solvent. Lithium hexafluorophosphate (LiPF6) was then dissolved in the base solvent to obtain the electrolyte. The mass percentage of LiPF6 in the electrolyte was 12.5%.

[0111] (5) Assembly of lithium-ion batteries

[0112] The positive electrode tab is installed in one of the second regions 342 of the positive electrode plate 410 by rolling, and the protective adhesive is pasted on the second region 342 of the positive electrode plate 410. The negative electrode tab is installed in the edge region of the negative electrode plate 420 by rolling.

[0113] The positive electrode 410 with positive tabs, the separator 50, and the negative electrode 420 with negative tabs are stacked sequentially, with the separator 50 positioned between the positive electrode 410 and the negative electrode 420 to provide insulation. The electrode body 20 is then formed by winding the separator. The electrode assembly is placed in an outer aluminum-plastic film package and dried in an 85°C vacuum oven for 12 hours to remove moisture. Electrolyte is then injected, and the lithium-ion battery is obtained through vacuum sealing, settling, formation, capacity testing, degassing, and edge trimming.

[0114] In Example 1-1, the positive electrode sheet has a protrusion. The protrusion is rolled out of the positive electrode sheet by rolling, and the electrode sheet shown in Figure 4 is used as the positive electrode sheet. The parameters of the lithium-ion battery are shown in Table I.

[0115] Table I

[0116] Comparative Example 1-1 is the same as Example 1-1 except that no protrusion is provided in the preparation of the positive electrode sheet.

[0117] Examples 1-2 to 1-14 and Comparative Examples 1-1 to 1-4 are the same as in Example 1-1, except that the center distance L between two adjacent protrusions and the viscosity η of the electrolyte at 25°C are adjusted as shown in Table 1 during the preparation of the positive electrode sheet. The viscosity η of the electrolyte at 25°C can be obtained by adjusting the proportion of each component in the base solvent.

[0118] The parameters and performance test results of the lithium-ion batteries of Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4 are shown in Table 1.

[0119] Table 1

[0120] Among them, the higher the number of charge-discharge cycles and the greater the liquid retention, the better the battery performance.

[0121] As can be seen from Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4 in Table 1, when the lithium-ion battery satisfies the following conditions: 0.5mm≤L≤4.0mm and 3.0≤η / L≤7.0, the spacing between two adjacent protrusions 311 can be matched with the viscosity η of the electrolyte. The protrusions 311 can provide sufficient support for the separator 50, and the electrolyte can flow smoothly between the protrusions 311, achieving better electrolyte storage, improving the wetting effect of the electrolyte, preventing local electrolyte shortage, and also improving the ion transport effect between the electrode 300 and the separator 50, improving the charge-discharge cycle performance of the lithium-ion battery at 25℃ and 45℃, and improving the electrolyte retention of the lithium-ion battery.

[0122] As can be seen from Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4 in Table 1, the electrolyte satisfies the following condition: 6.0 MPa·s ≤ η ≤ 14.0 MPa·s. The electrolyte can flow smoothly in the gap between the electrode 300 and the separator 50, improving the wetting effect of the electrolyte. The lithium-ion battery exhibits good charge-discharge cycle performance at 25°C and 45°C.

[0123] As can be seen from Examples 1-1 to 1-7 in Table 1, when the lithium-ion battery satisfies: 9.38≤L2 / (2HR-H) 2 With a value ≤105, it has a better effect on improving the charge-discharge cycle performance of lithium-ion batteries at 25℃ and 45℃.

[0124] The parameters and performance test results of the lithium-ion batteries in Examples 2-1 to 2-12 are shown in Table 2.

[0125] Table 2

[0126] As can be seen from Examples 2-1 to 2-3, Examples 2-9 to 2-10 and Examples 1-4 in Table 2, when the electrode 300 satisfies: 0.05mm≤H≤0.08mm, the height of the protrusion 311 is appropriate and can support the separator 50, making the gap between the electrode 300 and the separator 50 better, which can improve the wetting effect of the electrolyte, and the lithium-ion battery has good charge-discharge cycle performance at 25°C and 45°C.

[0127] As can be seen from Examples 2-4 to 2-8, Examples 2-11 to 2-12 and Examples 1-4 in Table 2, when the electrode 300 satisfies: 0.3mm≤R≤2.0mm, the degree of protrusion of the electrode 300 is appropriate, preventing the protrusion 311 from easily deforming under external force. The protrusion 311 has good supporting structural strength and can also better play the role of storing residual electrolyte, improving the electrolyte wetting effect. The lithium-ion battery has good charge-discharge cycle performance at 25℃ and 45℃.

[0128] The parameters and performance test results of the lithium-ion batteries in Examples 3-1 to 3-8 are shown in Table 3.

[0129] Table 3

[0130] As can be seen from Examples 3-1 to 3-4 and Examples 1-4 in Table 3, the projected area S of the outer surface 3112 of the protrusion 311 in the thickness direction Z of the electrode 300 satisfies: 0.16 mm. 2 With a value of ≤S≤2.0, the space occupied by the protrusion 311 is appropriate, providing a suitable space between the separator 50 and the main body 312 of the electrode 300 for accommodating the electrolyte. It also enhances the rigidity of the substrate, preventing wrinkling and bending of the substrate. The lithium-ion battery exhibits good charge-discharge cycle performance at 25°C and 45°C.

[0131] As can be seen from Examples 3-5 to 3-8 and Examples 1-4 in Table 3, the tensile strength T of the current collector satisfies: 100 MPa / mm. 2 ≤T / S≤200MPa / mm 2 With a strength of 30MPa≤T≤400MPa, the electrode 300 is not easily deformed or damaged. It can maintain the shape of the protrusion 311 when subjected to a large force, which improves the self-discharge performance of the battery. At the same time, under the influence of expansion force during charging and discharging, the electrode 300 has suitable ductility, which makes the lithium-ion battery have good charge and discharge cycle performance at 25℃ and 45℃.

[0132] The parameters and performance test results of the lithium-ion batteries in Examples 4-1 to 4-6 are shown in Table 4.

[0133] Table 4

[0134] As can be seen from Examples 4-1 to 4-6 and Examples 1-4 in Table 4, when the weight percentage of linear ester compounds is W, 40wt.%≤W≤60wt.%, the electrolyte can flow smoothly in the gap between the electrode 300 and the separator 50, improving the wetting effect of the electrolyte and resulting in good charge-discharge cycle performance of the lithium-ion battery at 25°C and 45°C.

[0135] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0136] The above description is merely a preferred embodiment of this application and is 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 protection scope of this application.

Claims

A type of battery, wherein, It includes an outer packaging, an electrode assembly, and an electrolyte, wherein the electrode assembly is disposed in the internal space of the outer packaging, and the electrolyte fills the internal space of the outer packaging; The electrode assembly includes an electrode sheet, which includes a main body and a plurality of protrusions. The protrusions are formed by a portion of the electrode sheet protruding towards the thickness direction of the main body. The center-to-center distance between two adjacent protrusions is L (mm), where 0.5 ≤ L ≤ 4.

0. The viscosity of the electrolyte at 25°C is η (mpa·s), 3.0≤η / L≤7.

0. According to claim 1, wherein, The battery satisfies at least one of the following conditions: (1)1.2≤L≤3.5； (3) 6 ≤ η / L ≤ 6.8; (2) 6.0 ≤ η ≤ 14.

0. According to claim 1, wherein, The height of the protrusion on the outer surface of the protrusion is H (mm), and the diameter of the inscribed ball on the inner surface of the protrusion is R (mm). 9.38 ≤ L² / (2HR-H) 2 )≤79.

75. The battery according to claim 3, wherein, The battery satisfies at least one of the following conditions: (1)0.05≤H≤0.08； (2)0.3≤R≤2.0。 The battery according to claim 3, wherein, The projected area of ​​the outer surface of the protrusion in the thickness direction of the electrode is S (mm²). 2 The electrode sheet satisfies at least one of the following conditions: (1)0.16≤S≤2.0； (2) 12.5 ≤ S / H ≤ 33.

3. The battery according to any one of claims 1-5, wherein, The electrode includes a current collector and an active material layer connected to the surface of the current collector; The tensile strength of the current collector is T (MPa), and the projected area of ​​the outer surface of the protrusion in the thickness direction of the electrode is S (mm). 2 ); The electrode sheet satisfies at least one of the following conditions: (1)30≤T≤400； (2) 100≤T / S≤200. The battery according to any one of claims 1-5, wherein, Multiple protrusions are arranged side by side and spaced apart along the first direction of the electrode to form a group of protrusion units. In the second direction of the electrode, adjacent groups of protrusion units are spaced apart. The first direction, the second direction and the thickness direction of the electrode are perpendicular to each other. The distance between two adjacent protrusions in the first direction and the second direction both satisfy the range of L. Wherein, the protrusions of two adjacent protrusion units are collinearly arranged in the second direction; or, One of the convex units is translated a predetermined distance A relative to the other convex unit in the first direction, where A satisfies: 0.3L≤A≤L. The battery according to any one of claims 1-5, wherein, In the thickness direction of the electrode sheet, all the protrusions are bent toward the same side of the main body; or, In the thickness direction of the electrode, a portion of the protrusions bends toward one side of the main body, and another portion of the protrusions bends toward the other side of the main body. The battery according to any one of claims 1-5, wherein, The electrolyte comprises linear ester compounds, and the weight percentage of the linear ester compounds is W, based on the total mass of the electrolyte, where 40 wt.% ≤ W ≤ 60 wt.%. The battery according to any one of claims 1-5, wherein, The electrode assembly includes a positive electrode, a negative electrode, and a separator, wherein the separator is disposed between the positive electrode and the negative electrode; At least one of the positive electrode and the negative electrode is the electrode with the protrusion. An electrical device, wherein, include: shell; and The battery according to any one of claims 1-10, wherein the battery is disposed in the internal space of the housing.

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