Electrode assembly, electrochemical device and electronic device

Abstract

The present application discloses an electrode assembly, an electrochemical device, and an electronic device. The electrode assembly according to an embodiment of the present application includes two electrode tabs and a separator. At least one electrode tab includes a main body portion and corner portions located on both sides of the main body portion. The main body portion includes a plurality of main body portion protrusions, the height of the main body portion protrusions being H1 (μm). The orthographic projection of the main body portion protrusions along the thickness direction of the electrode tab forms a first pattern, and the average radial dimension of the first pattern is R1 (mm). The corner portion includes a plurality of corner portion protrusions, the height of the corner portion protrusions being H2 (μm). The orthographic projection of the corner portion protrusions along the thickness direction forms a second pattern, and the average radial dimension of the second pattern is R2 (mm), satisfying: -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131. The separator includes a base film and an adhesive layer, the thickness of the adhesive layer being F (μm), and the electrode assembly satisfies: 4 ≤ H2 / F ≤ 800. The electrode assembly of the present application increases the interlayer gap between the separator and the electrode tab, making it easier for the electrolyte to enter the interior of the bare battery cell and improving the impregnation effect of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to an electrode assembly, an electrochemical device, and an electronic device. Background Art

[0002] Currently, the battery cells of secondary batteries usually adopt a winding structure. After winding, the battery cells need to be hot-pressed to fix the bare battery cells to prevent difficulties in subsequent casing. However, in this case, the wound battery cells after hot-pressing will cause problems that it is difficult for the electrolyte to enter the interior of the bare battery cells, thereby affecting the cycle performance of the battery cells. Summary of the Invention

[0003] Embodiments of the present application provide an electrode assembly, an electrochemical device, and an electronic device. The electrode assembly of the present application increases the interlayer gap between the separator and the electrode sheet, making it easier for the electrolyte to enter the interior of the bare battery cell, and improving the infiltration effect of the battery cell.

[0004] In a first aspect, embodiments of the present application provide an electrode assembly, including: at least two electrode sheets and a separator. The separator is disposed between two adjacent electrode sheets. The separator includes a base film and an inorganic layer, and the inorganic layer is coated on at least one side of the base film. At least one electrode sheet includes a main body portion and a corner portion located on the periphery of the main body portion. The main body portion includes a plurality of main body portion protrusions, the height of the main body portion protrusions is H1 (μm), and the orthographic projection of the main body portion protrusions along the thickness direction of the electrode sheet forms a first pattern (the orthographic projection in the present application refers to the orthographic projection observed from directly above the protrusion perpendicular to the plane where the protrusion is located). The average radial dimension of the first pattern is R1 (mm). The corner portion includes a plurality of corner portion protrusions, the height of the corner portion protrusions is H2 (μm), and the orthographic projection of the corner portion protrusions along the thickness direction forms a second pattern. The average radial dimension of the second pattern is R2 (mm). The main body portion protrusions and the corner portion protrusions satisfy: -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131. The separator includes a base film and an adhesive layer, and the adhesive layer is disposed on both sides of the base film. The thickness of the adhesive layer is F (μm). The electrode assembly satisfies: 4 ≤ H2 / F ≤ 800. The average radial dimension in the present application is the longest diameter of the first pattern formed by the orthographic projection of the protrusion along the thickness direction of the electrode sheet. In some specific embodiments, if the first pattern / second pattern formed by the orthographic projection is a circle, the average radial dimension is the diameter of the circle.

[0005] This application adjusts the characteristics of the protrusions on the main body and the corners, and when H1 / 1000R1-H2 / 1000R2 satisfies: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131, the electrolyte can be more evenly and efficiently infiltrated into various parts of the battery cell, greatly improving the wetting effect. At the same time, for the weak area interface in the battery cell that is prone to problems, the winding stress of the electrode assembly during winding and the expansion force of the electrode assembly are effectively buffered, thereby effectively improving the problems existing in the weak area interface such as ion transmission obstruction and poor interface stability, further improving the overall performance and stability of the battery cell and the cycle performance of the battery;

[0006] This application focuses on the ratio relationship between H and R, because H / 1000R can characterize the sharpness of the protrusion (bump). The smaller the H / 1000R, the smoother the protrusion, and the larger the H / 1000R, the sharper the protrusion. This application also focuses on the H / 1000R ratio difference between the main body and the corner area, that is, H1 / 1000R1-H2 / 1000R2. This relationship can characterize the difference between the protrusion structure of the main body and the protrusion structure of the corner. This application finds that this difference needs to meet the range limited by this application. When H1 / 1000R1-H2 / 1000R2 is greater than 0.0131, it means that the H1 value is large, which will make the gap between the layers of the battery cell too large, affecting the rapid transmission of lithium ions, thereby affecting the cycle, and will cause severe lithium precipitation after the cycle. In this case, the H1 value is large, which will increase the degree of damage to the pole piece, thereby worsening the battery cell processing quality rate. When H1 / 1000R1-H2 / 1000R2 is less than -0.2665, it means that the H1 value is small, the H2 value is large, and the gap between the layers in the main area is small, which affects the flow rate of the electrolyte between the layers, and the electrolyte infiltrates the pole piece poorly, which in turn affects the cycle performance and also causes serious lithium precipitation. Therefore, when H1 / 1000R1-H2 / 1000R2 meets the limited range of this application, the difference between the raised structure in the main area and the raised structure in the corner area can be satisfied within a suitable range, thereby improving the cycle performance of the battery at high current density and alleviating the phenomenon of lithium precipitation of the pole piece after the battery is cycled at high current density, thereby improving the winding superiority.

[0007] On this basis, the corner protrusion cooperates with the adhesive layer to keep the separator film in a stable position inside the battery, reduce the risk of displacement, wrinkles or breakage, improve the regularity of the internal structure of the battery, enhance the stability of the battery during charging and discharging, and facilitate better penetration and diffusion of the electrolyte between the electrode sheet and the separator film, enabling the electrolyte to fully wet the electrode sheet and the separator film, improving the ion transport efficiency, and further enhancing the charge and discharge performance and rate performance of the battery. At the same time, the adhesive layer tightly combines the separator film with the corner protrusion and the main body protrusion to form a stable interface, reduce the resistance at the interface, and lower the energy loss of the battery during charging and discharging.

[0008] In some specific embodiments, the main body protrusion satisfies: 0.0005 ≤ H1 / 1000R1 ≤ 0.133, and / or, the corner protrusion satisfies: 0.002 ≤ H2 / 1000R2 ≤ 0.267.

[0009] In this specific embodiment, the main body protrusion satisfies: 0.0005 ≤ H1 / 1000R1 ≤ 0.0151, and / or, the corner protrusion satisfies: 0.002 ≤ H2 / 1000R2 ≤ 0.267, which can better improve the wetting effect of the electrolyte on the battery cell and further enhance the overall performance and stability of the battery cell.

[0010] In some specific embodiments, the main body protrusion satisfies: 0.015 ≤ H1 / 1000R1 ≤ 0.025, and / or, the corner protrusion satisfies: 0.0167 ≤ H2 / 1000R2 ≤ 0.025. The main body protrusion and the corner protrusion provide effective support for the separator film, keeping the separator film in a stable position and shape inside the battery, preventing the separator film from shifting, deforming or breaking during the winding of the electrode assembly or the use of the battery, ensuring that the separator film can normally play the role of isolating the positive and negative electrodes and preventing short circuits, and improving the safety and stability of the battery.

[0011] In some specific embodiments, the electrode assembly satisfies at least one of the following: (1) 5 ≤ H1 ≤ 35; (2) 20 ≤ H2 ≤ 80; (3) 0.3 ≤ R1 ≤ 10; (4) 0.3 ≤ R2 ≤ 10.

[0012] In this specific embodiment, when the main body protrusion and the corner protrusion satisfy one of the above conditions, the main body protrusion and the corner protrusion can better improve the wetting effect of the electrolyte on the battery cell and further enhance the overall performance and stability of the battery cell.

[0013] In some specific embodiments, the separator film may further include an inorganic layer, which is disposed between the base film and the adhesive layer. The thickness of the inorganic layer is D (μm), and the electrode assembly satisfies: 3.3 ≤ H2 / D ≤ 160.

[0014] In the above specific embodiments, the electrode assembly satisfies: 3.3 ≤ H2 / D ≤ 160. When the thickness of the inorganic layer in the electrode assembly and the height H2 of the corner protrusion satisfy the above conditions, the inorganic layer has good ionic conductivity and can provide a smooth transmission channel for lithium ions. A channel conducive to the flow of the electrolyte is formed between the electrode plate and the separator, ensuring that lithium ions in the electrolyte can quickly reach the surface of the inorganic layer. The cooperation of the two makes the transmission of lithium ions between the electrode and the electrolyte more efficient, thereby improving the charge and discharge rate of the battery.

[0015] Meanwhile, the inorganic layer and the corner protrusion structure act synergistically to disperse the stress generated by the electrode plate to a larger area, avoid stress concentration, effectively protect the integrity of the internal structure of the battery, and improve the cycle stability of the battery.

[0016] In some specific embodiments, the electrode assembly satisfies: 6.7 ≤ H2 / D ≤ 60.

[0017] In the above specific embodiments, the electrode assembly satisfies: 6.7 ≤ H2 / D ≤ 60, which can further enhance the strength of the electrode assembly, reduce the problem of separator puncture during battery use, and improve the wetting effect of the electrolyte at the same time.

[0018] In some specific embodiments, the separator may further include an inorganic layer. The inorganic layer is disposed between the base film and the adhesive layer. The thickness of the inorganic layer is D (μm). The value ranges of the thickness D of the inorganic layer and the height H2 of the corner protrusion are respectively: 0.5 ≤ D ≤ 6, 20 ≤ H2 ≤ 80.

[0019] In the above specific embodiments, the synergistic effect of the inorganic layer and the corner protrusion can effectively enhance the strength of the electrode assembly, reduce the problem of separator puncture during battery use, and improve the wetting effect of the electrolyte at the same time.

[0020] In some specific embodiments, the value ranges of the thickness D of the inorganic layer and the height H2 of the corner protrusion are respectively: 1 ≤ D ≤ 3, 20 ≤ H2 ≤ 60.

[0021] In the above specific embodiments, the synergistic effect of the inorganic layer and the corner protrusion can further enhance the strength of the electrode assembly, further reduce the problem of separator puncture during battery use, and improve the wetting effect of the electrolyte at the same time.

[0022] In some specific embodiments, the separator may further include an inorganic layer. The inorganic layer is disposed between the base film and the adhesive layer. The inorganic layer includes inorganic particles. The average particle size of the inorganic particles is E (μm). The electrode assembly satisfies: 10 ≤ H2 / E ≤ 800.

[0023] In the above specific embodiments, the electrode assembly satisfies: 10 ≤ H2 / E ≤ 800. The inorganic particles and the corner protrusions act synergistically to buffer the stress caused by the volume change of the electrode material during the charge and discharge of the battery, reducing the risk of structural damage and pulverization of the electrode material. At the same time, the two act synergistically to optimize the interfacial contact between the electrode and the electrolyte, making the charge transfer process easier to carry out and reducing the charge transfer resistance.

[0024] In some specific embodiments, the electrode assembly satisfies: 20 ≤ H2 / E ≤ 180.

[0025] In the above specific embodiments, the electrode assembly satisfies: 20 ≤ H2 / E ≤ 180. The inorganic particles and the corner protrusions act synergistically to further improve the electrolyte infiltration effect, battery efficiency and battery safety.

[0026] In some specific embodiments, the separator membrane may further include an inorganic layer. The inorganic layer is disposed between the base film and the adhesive layer. The inorganic layer includes inorganic particles. The average particle size of the inorganic particles is E (μm). The value ranges of the average particle size E of the inorganic particles and the height H2 of the corner protrusions are respectively: 0.1 ≤ E ≤ 2, 20 ≤ H2 ≤ 80.

[0027] In the above specific embodiments, the corner protrusions and the inorganic particles act synergistically to increase the surface roughness and irregularity of the electrode assembly, increasing the contact points and contact area between the electrolyte and the electrode sheet. At the same time, the inorganic particles can fill the channels formed by the corner protrusions. On the one hand, it makes the channels more stable and regular. On the other hand, the pores between the inorganic particles can also serve as microscopic channels for electrolyte transmission, allowing the electrolyte to penetrate more deeply into the material interior, thereby improving the electrolyte infiltration effect, battery efficiency and battery safety.

[0028] In some specific embodiments, the inorganic layer includes inorganic particles. The particle size of the inorganic particles is E. The value ranges of the average particle size E of the inorganic particles and the height H2 of the corner protrusions are respectively: 0.3 ≤ E ≤ 1, 20 ≤ H2 ≤ 60.

[0029] In the above specific embodiments, the corner protrusions and the inorganic particles act synergistically to increase the surface roughness and irregularity of the electrode assembly while further improving the microscopic structure of the channels formed by the inorganic particles filled in the corner protrusions, thereby further improving the electrolyte infiltration effect, battery efficiency and battery safety.

[0030] In some specific embodiments, the electrode assembly satisfies at least one of the following: (1) The adhesive layer includes adhesive particles, the average particle size of the adhesive particles is G (μm), and 10 ≤ H2 / G ≤ 800. When 10 ≤ H2 / G ≤ 800, the adhesive particles in the adhesive layer can fill the tiny gaps between the corner protrusions and the main body protrusions and the separator film, making the adhesion between the two closer and stronger, so that the separator film is not easily displaced or detached inside the battery, improving the stability of the internal structure of the battery. The corner protrusions, the main body protrusions, and the adhesive particles on the adhesive layer work together to optimize the transmission path of the electrolyte between the electrode sheet and the separator film, improve the adsorption and diffusion of the electrolyte, enable the electrolyte to be more evenly distributed around the electrode sheet and the separator film, improve the ion transport efficiency, and further enhance the charge-discharge performance and rate performance of the battery; (2) The pore size of the adhesive layer is P (μm), and 0.2 ≤ H2 / P ≤ 160. When 0.2 ≤ H2 / P ≤ 160, the electrolyte can be more evenly distributed around the electrode sheet and the separator film, improving the ion transport efficiency, and further enhancing the charge-discharge performance and rate performance of the battery; (3) The pore size of the adhesive layer is P (μm), and 3 ≤ 1000R2 / P ≤ 20000. When 3 ≤ 1000R2 / P ≤ 20000, the adhesive layer has better flexibility and deformability, can more effectively buffer stress, avoid damage to the separator film due to local stress concentration, and extend the service life of the separator film and the battery.

[0031] In some specific embodiments, the electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F (μm), and 10 ≤ H2 / F ≤ 120; (2) The adhesive layer includes adhesive particles, the average particle size of the adhesive particles is G (μm), and 20 ≤ H2 / G ≤ 600; (3) The pore size of the adhesive layer is P (μm), and 0.4 ≤ H2 / P ≤ 120; (4) The pore size of the adhesive layer is P (μm), and 20 ≤ 1000R2 / P ≤ 6000.

[0032] In some specific embodiments, the electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F (μm), and the value ranges of the thickness F of the adhesive layer and the height H2 of the corner protrusion are: 0.1 ≤ F ≤ 5, 20 ≤ H2 ≤ 80; (2) The adhesive layer includes adhesive particles, the average particle size of the adhesive particles is G (μm), and the value ranges of the average particle size G of the adhesive particles and the height H2 of the corner protrusion are: 0.1 ≤ G ≤ 2, 20 ≤ H2 ≤ 80; (3) The pore size of the adhesive layer is P (μm), and the value ranges of the pore size P of the adhesive layer and the height H2 of the corner protrusion are: 0.5 ≤ P ≤ 100, 20 ≤ H2 ≤ 80; (4) The pore size of the adhesive layer is P (μm), and the value ranges of the pore size P of the adhesive layer and the average radial dimension R2 of the second pattern are: 0.5 ≤ P ≤ 100, 0.3 ≤ R2 ≤ 10.

[0033] In the above specific embodiments, the electrode assembly satisfies one of the above conditions. The bonding layer's combination with the raised structure can improve the wetting ability of the battery cell, enhance the liquid retention ability of the battery, thereby reducing the battery impedance, improving the cycling ability, and further enhancing the heat dissipation ability of the battery cell, achieving improvement in gas generation during high-temperature storage and improvement in hot box performance.

[0034] In some specific embodiments, the electrode assembly satisfies at least one of the following: (1) The thickness of the bonding layer is F (μm), and the value ranges of the thickness F of the bonding layer and the height H2 of the corner protrusion are respectively: 0.5 ≤ F ≤ 2, 20 ≤ H2 ≤ 60; (2) The bonding layer includes bonding particles, and the average particle size of the bonding particles is G (μm), and the value ranges of the average particle size G of the bonding particles and the height H2 of the corner protrusion are respectively: 0.1 ≤ G ≤ 1, 20 ≤ H2 ≤ 60; (3) The pore size of the bonding layer is P (μm), and the value ranges of the pore size P of the bonding layer and the height H2 of the corner protrusion are respectively: 0.5 ≤ P ≤ 50, 20 ≤ H2 ≤ 60; (4) The pore size of the bonding layer is P, and the value ranges of the pore size P of the bonding layer and the average radial dimension R2 of the second pattern are respectively: 0.5 ≤ P ≤ 50, 1 ≤ R2 ≤ 3.

[0035] In the above specific embodiments, the electrode assembly satisfies one of the above conditions. The bonding layer's combination with the raised structure can improve the wetting ability of the battery cell, enhance the liquid retention ability of the battery, thereby reducing the battery impedance, improving the cycling ability, and further enhancing the heat dissipation ability of the battery cell, achieving improvement in gas generation during high-temperature storage and improvement in hot box performance.

[0036] In some specific embodiments, at least two electrode plates and a separator are wound around a core to form an electrode assembly. The main body protrusion protrudes from the main body towards the core, and the corner protrusion protrudes from the corner towards the core or protrudes from the corner away from the core.

[0037] In the above specific embodiments, the corner protrusion facing the core can occupy a certain space inside the core, making the internal structure of the core more compact, accommodating more active materials or other components in the limited battery space, which is beneficial to improving the energy density of the battery; the corner protrusion facing away from the core can form a buffer between the core and external structures such as the battery casing, reducing the direct collision and friction between the core and the casing when the core is subjected to external force impact or vibration, thereby protecting the battery casing and internal structure and reducing the possibility of battery damage caused by external factors, improving the safety and reliability of the battery.

[0038] In a second aspect, an embodiment of the present application provides an electrochemical device, including: a housing and at least one electrode assembly of the first aspect, and the electrode assembly is disposed inside the housing.

[0039] In a third aspect, an embodiment of the present application provides an electronic device configured to receive electrical energy provided by the electrochemical device of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The features, advantages, and technical effects of exemplary embodiments of the present application will be described below with reference to the drawings.

[0041] Figure 1 FIG. [X] is a schematic structural diagram of an electrode assembly according to an embodiment of the present application;

[0042] Figure 2 FIG. [X] is a schematic structural diagram of a tab bulge according to an embodiment of the present application;

[0043] Figure 3 FIG. [X] is a schematic diagram of the spacing setting between tab bulges according to an embodiment of the present application.

[0044] In the drawings, the drawings are not necessarily drawn to actual scale. DETAILED DESCRIPTION

[0045] Embodiments of the present application will be described in detail below. Embodiments of the present application should not be construed as limiting the present application.

[0046] As used in the present application, the terms "comprising", "including", and "containing" are used in their open, non-limiting sense.

[0047] In addition, quantities, ratios, and other numerical values are sometimes presented herein in a range format. It should be understood that such range formats are for convenience and brevity, and should be understood flexibly, including not only the explicitly specified numerical values as range limits, but also all individual numerical values or sub-ranges subsumed within the said range, as if each numerical value and sub-range were explicitly specified.

[0048] In the detailed description and claims, a list of items connected by the terms "one or more of", "one or more among", "at least one of", or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A or B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may include a single element or multiple elements. Item B may include a single element or multiple elements. Item C may include a single element or multiple elements.

[0049] Note: In the above translation, the references to "FIG. [X]" are placeholders for the actual figure numbers which are not provided in the original text. You may need to replace them with the correct figure numbers according to the actual content.The separator and two electrode plates are wound around multiple times along the length direction of the electrode plate. The length direction of the electrode plate is the direction in which the electrode plate is wound, and the width direction is perpendicular to the length direction. The electrode assembly is flat. Each turn of the electrode plate includes two main body parts and two corner parts, and the two main body parts are connected between the two corner parts. Among them, the corner parts of adjacent turns of the electrode plate are prone to extrusion with each other, and there is also extrusion between the main body part and the corner part of each turn of the electrode plate. Therefore, the corner part is a high-incidence area of extrusion in the electrode assembly. When extrusion occurs in the corner part, problems such as insufficient electrolyte and poor infiltration are likely to occur, which in turn leads to deterioration of the electrode interface in the corner part and even cyclic failure.

[0050] Based on the above situation, the embodiments of the present application provide an electrode assembly, an electrochemical device, and an electronic device. The electrode assembly of the present application increases the interlayer gap between the separator and the electrode plate, making it easier for the electrolyte to enter the internal part of the bare battery cell, and improving the infiltration effect of the battery cell.

[0051] The following will detail the implementation manners of the present application.

[0052] Electrode assembly

[0053] In the first aspect, the embodiments of the present application provide an electrode assembly, as Figure 1 shown. The electrode assembly of the embodiments of the present application includes two electrode plates with opposite polarities and a separator disposed between the two electrode plates. Moreover, the length direction (Machine Direction, MD direction), width direction (Transverse Direction, TD direction), and thickness direction of the two electrode plates with opposite polarities are the same, and the separator is disposed between the two electrode plates with opposite polarities in the thickness direction of the electrode plates. One of the two electrode plates with opposite polarities is a positive electrode plate, and the other is a negative electrode plate. The separator has insulation properties to separate the positive electrode plate and the negative electrode plate to prevent short circuit.

[0054] Multiple electrode plate protrusions (also referred to as electrode plate bumps) are provided on at least one of the two electrode plates, as Figure 2As shown, the height of the pole piece protrusion is H (μm), and the average radial dimension of the figure formed by the orthographic projection of the pole piece protrusion along the thickness direction of the pole piece is R (mm). Specifically, the pole piece includes a main body part and corner parts provided at both ends of the main body part. The main body part includes a plurality of main body part protrusions (also referred to as main body part bumps), the height of the main body part protrusions is H1 (μm), the orthographic projection of the main body part protrusions along the thickness direction of the pole piece forms a first figure, and the average radial dimension of the first figure is R1 (mm). The corner parts include a plurality of corner part protrusions (also referred to as corner part bumps), the height of the corner part protrusions is H2 (μm), the orthographic projection of the corner part protrusions along the thickness direction forms a second figure, and the average radial dimension of the second figure is R2 (mm). In this pole piece, the main body part protrusions and the corner part protrusions satisfy: -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131; the separator includes a base film and an adhesive layer, the adhesive layer is provided on both sides of the base film, the thickness of the adhesive layer is F (μm), and the electrode assembly satisfies: 4 ≤ H2 / F ≤ 800.

[0055] For example, H1 / 1000R1 - H2 / 1000R2 can be -0.2665, -0.25, -0.22, -0.2, -0.18, -0.15, -0.12, -0.1, -0.08, -0.05, -0.02, 0, 0.01, 0.131, or a range composed of any of the above values.

[0056] H2 / F can be 4, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, or a range composed of any of the above values.

[0057] Optionally, -0.25 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.2 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.15 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.1 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.05 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.015 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.01, -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0083.

[0058] Optional, 10≤H2 / F≤750, 10≤H2 / F≤700, 10≤H2 / F≤650, 10H2 / F≤600, 10≤H2 / F≤550, 10≤H2 / F≤500, 10≤H2 / F≤450, 10≤H2 / F≤400, 10≤H2 / F≤350, 10≤H2 / F≤300, 10≤H2 / F≤250, 10≤H2 / F≤200, 10≤H2 / F≤150, 10≤H2 / F≤120.

[0059] According to the present application, by adjusting the characteristics of the protrusions on the main body and the protrusions on the corners, when H1 / 1000R1-H2 / 1000R2 satisfies: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131, the electrolyte can be more evenly and efficiently infiltrated into various parts of the battery cell, greatly improving the wetting effect. At the same time, for the weak area interface in the battery cell that is prone to problems, the winding stress during the winding process of the electrode assembly and the expansion force of the electrode assembly are effectively buffered, thereby effectively improving the problems existing in the weak area interface such as obstructed ion transmission and poor interface stability, further improving the overall performance and stability of the battery cell and the cycle performance of the battery.

[0060] This application focuses on the ratio relationship between H and R, because H / 1000R can characterize the sharpness of the protruding structure. The smaller H / 1000R is, the smoother the protruding structure is. The larger H / 1000R is, the sharper the protruding structure is. This application also focuses on the H / 1000R ratio difference between the main body and the corner area, that is, H1 / 1000R1-H2 / 1000R2. This relationship can characterize the difference between the protrusion in the main area and the protrusion in the corner area. This application finds that this difference needs to meet the range limited by this application. When H1 / 1000R1-H2 / 1000R2 is greater than 0.0131, it means that the H1 value is large, which will make the gap between the battery cell layers too large, affecting the rapid transmission of lithium ions, and thus affecting the cycle, and will cause severe lithium precipitation after the cycle. In this case, the H1 value is large, which will increase the degree of damage to the pole piece, thereby deteriorating the battery cell processing quality rate. When H1 / 1000R1-H2 / 1000R2 is less than -0.2665, it means that the H1 value is small, the H2 value is large, and the gap between the layers in the main area is small, which affects the flow rate of the electrolyte between the layers, and the electrolyte infiltrates the pole piece poorly, which in turn affects the cycle performance and also causes serious lithium precipitation. Therefore, when H1 / 1000R1-H2 / 1000R2 meets the limited range of this application, the difference between the raised structure in the main area and the raised structure in the corner area can be satisfied within a suitable range, thereby improving the cycle performance of the battery at high current density and alleviating the phenomenon of lithium precipitation of the pole piece after the battery is cycled at high current density, thereby improving the winding superiority.

[0061] On this basis, the protrusions on the corners cooperate with the adhesive layer to keep the isolation membrane in a stable position inside the battery, reduce the risk of displacement, wrinkling or damage, improve the regularity of the internal structure of the battery, and improve the stability of the battery during charging and discharging. It is also beneficial for the electrolyte to better penetrate and diffuse between the electrode and the isolation membrane, so that the electrolyte can fully infiltrate the electrode and the isolation membrane, improve the ion transfer efficiency, and thereby improve the battery's charge and discharge performance and rate performance. At the same time, the adhesive layer tightly combines the isolation membrane with the protrusions on the corners and the protrusions on the main body to form a stable interface, reduce the resistance at the interface, and reduce the energy loss of the battery during charging and discharging.

[0062] The above is only an exemplary introduction. The present application does not limit the orientation of the main body protrusion and the corner protrusion of each pole piece, and the specific orientation can be selected according to actual needs.

[0063] It should be noted that the height H1 (μm) of the main body protrusion, the diameter R1 (mm) of the projection of the main body protrusion along the thickness direction of the pole piece, the height H2 (μm) of the corner protrusion, the diameter R2 (mm) of the projection of the corner protrusion along the thickness direction of the pole piece, and the thickness F (μm) of the bonding layer can all be detected using methods and instruments known in the art. For example, the pole piece can be obtained by disassembling the electrochemical device, and the pole piece sample can be placed in a scanning electron microscope using a scanning electron microscope (SEM) measurement method, and a high-resolution image of the protruding structure can be obtained by electron beam scanning. In the SEM image, the image processing software can be used to draw a measurement line along the height direction of the protruding structure, and the height of the protruding structure can be calculated based on the pixel information of the image and the known magnification. Similarly, in the SEM image, the diameter of the protruding structure is measured by the image processing software to obtain the radius. It can also be measured by a VR series shape profile measurement microscope. The isolation film can be obtained by disassembling the electrochemical device, and the isolation film can be sliced ​​using the scanning electron microscope (SEM) measurement method to prepare a flat cross-sectional sample. The sample is placed in the SEM device, and the appropriate acceleration voltage and scanning parameters are selected to obtain a high-resolution cross-sectional image. The thickness F of the bonding layer can be directly measured on the image using the image processing software provided by the SEM.

[0064] In some embodiments, the protrusion of the main body satisfies: 0.0005≤H1 / 1000R1≤0.133, and / or the protrusion of the corner portion satisfies: 0.002≤H2 / 1000R2≤0.267.

[0065] For example, H1 / 1000R1 can be 0.0005, 0.001, 0.002, 0.005, 0.01, 0.015, 0.0151, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.133, or a range composed of any of the above numerical values.

[0066] For example, H2 / 1000R2 can be 0.002, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.267, or a range composed of any of the above numerical values.

[0067] Optionally, 0.001 ≤ H1 / 1000R1 ≤ 0.133, 0.002 ≤ H1 / 1000R1 ≤ 0.133, 0.005 ≤ H1 / 1000R1 ≤ 0.133, 0.008 ≤ H1 / 1000R1 ≤ 0.133, 0.01 ≤ H1 / 1000R1 ≤ 0.133, 0.01 ≤ H1 / 1000R1 ≤ 0.1, 0.01 ≤ H1 / 1000R1 ≤ 0.08, 0.01 ≤ H1 / 1000R1 ≤ 0.06, 0.01 ≤ H1 / 1000R1 ≤ 0.04, 0.01 ≤ H1 / 1000R1 ≤ 0.025.

[0068] Optionally, 0.005 ≤ H2 / 1000R2 ≤ 0.267, 0.008 ≤ H2 / 1000R2 ≤ 0.267, 0.01 ≤ H2 / 1000R2 ≤ 0.267, 0.012 ≤ H2 / 1000R2 ≤ 0.267, 0.015 ≤ H2 / 1000R2 ≤ 0.267, 0.0167 ≤ H2 / 1000R2 ≤ 0.267, 0.0167 ≤ H2 / 1000R2 ≤ 0.2, 0.0167 ≤ H2 / 1000R2 ≤ 0.15, 0.0167 ≤ H2 / 1000R2 ≤ 0.1, 0.0167 ≤ H2 / 1000R2 ≤ 0.08, 0.0167 ≤ H2 / 1000R2 ≤ 0.06, 0.0167 ≤ H2 / 1000R2 ≤ 0.04, 0.0167 ≤ H2 / 1000R2 ≤ 0.025.

[0069] In the above embodiments, the protrusion of the main body portion satisfies: 0.0005 ≤ H1 / 1000R1 ≤ 0.133, and / or, the protrusion of the corner portion satisfies: 0.002 ≤ H2 / 1000R2 ≤ 0.267. The protrusions of the main body portion and the corner portion provide effective support for the separator, enabling the separator to maintain a stable position and shape inside the battery, preventing the separator from shifting, deforming or breaking during the winding of the electrode assembly or the use of the battery, ensuring that the separator can normally perform the functions of isolating the positive and negative electrodes and preventing short circuits, and improving the safety and stability of the battery.

[0070] In some embodiments, the electrode assembly satisfies at least one of the following: (1) 5 ≤ H1 ≤ 40. For example, H1 can be 20, 30, 35, 40, 50, 60, 70, 80, or a range composed of any of the above values; (2) 20 ≤ H2 ≤ 80. For example, H2 can be 20, 30, 40, 50, 60, 70, 80, or a range composed of any of the above values; (3) 0.3 ≤ R1 ≤ 10. For example, R1 can be 0.3, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or a range composed of any of the above values; (4) 0.3 ≤ R2 ≤ 10. For example, R2 can be 0.3, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or a range composed of any of the above values.

[0071] When the electrode assembly satisfies any one of the above in the above embodiments, the protrusions of the main body portion and the corner portion can better improve the wetting effect of the electrolyte on the battery cell, and further improve the overall performance and stability of the battery cell.

[0072] In some embodiments, the separator may further include an inorganic layer. The inorganic layer is disposed between the base film and the adhesive layer, and the thickness of the inorganic layer is D (μm). The electrode assembly satisfies: 3.3 ≤ H2 / D ≤ 160. For example, H2 / D can be 3.3, 5, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150, 160, or a range composed of any of the above values.

[0073] Optionally, 6.7 ≤ H2 / D ≤ 160, 6.7 ≤ H2 / D ≤ 150, 6.7 ≤ H2 / D ≤ 140, 6.7 ≤ H2 / D ≤ 130, 6.7 ≤ H2 / D ≤ 120, 6.7 ≤ H2 / D ≤ 110, 6.7 ≤ H2 / D ≤ 100, 6.7 ≤ H2 / D ≤ 90, 6.7 ≤ H2 / D ≤ 80, 6.7 ≤ H2 / D ≤ 70, 6.7 ≤ H2 / D ≤ 60.

[0074] In the above embodiment, the electrode assembly satisfies: 3.3≤H2 / D≤160. When the thickness of the inorganic layer in the electrode assembly and the height H2 of the protrusion at the corner meet the above conditions, the inorganic layer has good ion conductivity and can provide a smooth transmission channel for lithium ions. A channel is formed between the pole piece and the isolation membrane to facilitate the flow of electrolyte, ensuring that the lithium ions in the electrolyte can quickly reach the surface of the inorganic layer. The combination of the two makes the transmission of lithium ions between the electrode and the electrolyte more efficient, thereby improving the charge and discharge rate of the battery.

[0075] At the same time, the inorganic layer and the protrusions on the corners work together to disperse the stress generated by the pole piece to a larger area, avoiding stress concentration, effectively protecting the integrity of the internal structure of the battery, and improving the cycle stability of the battery.

[0076] It should be noted that the thickness D (μm) of the inorganic layer can be detected using methods and instruments known in the art. For example, the isolation membrane can be obtained by disassembling the electrochemical device, and the isolation membrane can be sliced ​​using a scanning electron microscope (SEM) measurement method to prepare a flat cross-sectional sample. The sample is placed in the SEM device, and a suitable acceleration voltage and scanning parameters are selected to obtain a high-resolution cross-sectional image. The thickness of the inorganic layer can be directly measured on the image using the image processing software provided by the SEM.

[0077] In some embodiments, the isolation film may further include an inorganic layer, the inorganic layer is disposed between the base film and the adhesive layer, the thickness of the inorganic layer is D (μm), and the thickness D of the inorganic layer and the height H2 of the protrusion of the corner portion are in the range of 0.5≤D≤6, 20≤H2≤80. For example, D may be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or a range consisting of any of the above values. H2 may be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range consisting of any of the above values.

[0078] Optional, 1≤D≤6, 1≤D≤5.5, 1≤D≤5, 1≤D≤4.5, 1≤D≤4, 1≤D≤3.5, 1≤D≤3.

[0079] Optional, 20≤H2≤78, 20≤H2≤76, 20≤H2≤74, 20≤H2≤72, 20≤H2≤70, 20≤H2≤68, 20≤H2≤66, 20≤H2≤64, 20≤H2≤62, 20≤H2≤60.

[0080] In the above embodiments, the synergistic effect of the inorganic layer and the corner protrusions can effectively enhance the strength of the electrode assembly, reduce the problem of diaphragm puncture during battery use, and improve the infiltration effect of the electrolyte.

[0081] In some embodiments, the isolation film may further include an inorganic layer, the inorganic layer is disposed between the base film and the adhesive layer, the inorganic layer includes inorganic particles, the particle size of the inorganic particles is E (μm), and the electrode assembly satisfies: 10≤H2 / E≤800. For example, H2 / E may be 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, or a range consisting of any of the above values.

[0082] Optional, 20≤H2 / E≤750, 20≤H2 / E≤700, 20≤H2 / E≤650, 20≤H2 / E≤600, 20≤H2 / E≤550, 20≤H2 / E≤500, 20≤H2 / E≤450, 20≤H2 / E≤400, 20≤H2 / E≤350, 20≤H2 / E≤300, 20≤H2 / E≤250, 20≤H2 / E≤200, 20≤H2 / E≤180.

[0083] In the above embodiment, the electrode assembly satisfies: 10≤H2 / E≤800, and the inorganic particles and the corner protrusions work together to buffer the stress caused by the volume change of the electrode material during the battery charging and discharging process, reducing the risk of structural damage and pulverization of the electrode material. At the same time, the two work together to optimize the interface contact between the electrode and the electrolyte, making the charge transfer process easier and reducing the charge transfer resistance.

[0084] It should be noted that the particle size E (μm) of the inorganic particles can be detected using methods and instruments known in the art. For example, the isolation membrane can be obtained by disassembling the electrochemical device, and the isolation membrane sample containing the inorganic layer can be dried, fixed, and the like using a scanning electron microscope (SEM) measurement method. Then the sample is placed in the SEM device, and a suitable acceleration voltage and magnification are selected to obtain a high-resolution image of the inorganic particles. Finally, the image processing software provided by the SEM is used to directly measure the particle size of the inorganic particles on the image. The particle size can be characterized by measuring the maximum diameter, minimum diameter, or equivalent diameter of the particles.

[0085] In some embodiments, the separator membrane may further include an inorganic layer disposed between the base film and the adhesive layer. The inorganic layer includes inorganic particles with a particle size of E (μm). The value ranges of the average particle size E of the inorganic particles and the height H2 of the protrusion at the corner are respectively: 0.1 ≤ E ≤ 2, 20 ≤ H2 ≤ 80. For example, E can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or a range composed of any of the above values. H2 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range composed of any of the above values.

[0086] Optionally, 0.2 ≤ E ≤ 2, 0.3 ≤ E ≤ 2, 0.3 ≤ E ≤ 1.8, 0.3 ≤ E ≤ 1.6, 0.3 ≤ E ≤ 1.4, 0.3 ≤ E ≤ 1.2, 0.3 ≤ E ≤ 1.

[0087] Optionally, 20 ≤ H2 ≤ 78, 20 ≤ H2 ≤ 76, 20 ≤ H2 ≤ 74, 20 ≤ H2 ≤ 72, 20 ≤ H2 ≤ 70, 20 ≤ H2 ≤ 68, 20 ≤ H2 ≤ 66, 20 ≤ H2 ≤ 64, 20 ≤ H2 ≤ 62, 20 ≤ H2 ≤ 60.

[0088] In the above embodiments, the protrusion at the corner and the inorganic particles act synergistically to increase the surface roughness and irregularity of the electrode assembly, increasing the contact points and contact area between the electrolyte and the electrode sheet. At the same time, the inorganic particles can fill the channels formed by the protrusions at the corners. On the one hand, this makes the channels more stable and regular. On the other hand, the pores between the inorganic particles can also serve as microscopic channels for electrolyte transmission, allowing the electrolyte to penetrate more deeply into the material interior, thereby improving the electrolyte infiltration effect, battery efficiency, and battery safety.

[0089] In some embodiments, the electrode assembly satisfies at least one of the following: (1) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G (μm), and 10 ≤ H2 / G ≤ 800. For example, H2 / G can be 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, or a range composed of any of the above values. When 10 ≤ H2 / G ≤ 800, the adhesive particles in the adhesive layer can fill the tiny gaps between the corner protrusions and the main body protrusions and the separator film, making the adhesion between the two closer and stronger, so that the separator film is not easily displaced or detached inside the battery, improving the stability of the internal structure of the battery. The corner protrusions, the main body protrusions, and the adhesive particles on the adhesive layer work together to optimize the transmission path of the electrolyte between the electrode sheet and the separator film, improve the adsorption and diffusion of the electrolyte, enable the electrolyte to be more evenly distributed around the electrode sheet and the separator film, improve the ion transmission efficiency, and thus enhance the charge-discharge performance and rate performance of the battery; (2) The pore size of the adhesive layer is P (μm), and 0.2 ≤ H2 / P ≤ 160. For example, H2 / P can be 0.2, 0.5, 1, 3, 5, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150, 160, or a range composed of any of the above values. When 0.2 ≤ H2 / P ≤ 160, the electrolyte can be more evenly distributed around the electrode sheet and the separator film, improve the ion transmission efficiency, and thus enhance the charge-discharge performance and rate performance of the battery; (3) The pore size of the adhesive layer is P (μm), and 3 ≤ 1000R2 / P ≤ 20000. For example, 1000R2 / P can be 3, 10, 50, 100, 200, 500, 800, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, or a range composed of any of the above values. When 3 ≤ 1000R2 / P ≤ 20000, the adhesive layer has better flexibility and deformability, can more effectively buffer stress, avoid damage to the separator film due to local stress concentration, and extend the service life of the separator film and the battery.

[0090] Optionally, 20 ≤ H2 / G ≤ 780, 20 ≤ H2 / G ≤ 760, 20 ≤ H2 / G ≤ 740, 20 ≤ H2 / G ≤ 720, 20 ≤ H2 / G ≤ 700, 20 ≤ H2 / G ≤ 680, 20 ≤ H2 / G ≤ 660, 20 ≤ H2 / G ≤ 640, 20 ≤ H2 / G ≤ 620, 20 ≤ H2 / G ≤ 600.

[0091] Optionally, 0.4 ≤ H2 / P ≤ 160, 0.4 ≤ H2 / P ≤ 155, 0.4 ≤ H2 / P ≤ 150, 0.4 ≤ H2 / P ≤ 145, 0.4 ≤ H2 / P ≤ 140, 0.4 ≤ H2 / P ≤ 135, 0.4 ≤ H2 / P ≤ 130, 0.4 ≤ H2 / P ≤ 125, 0.4 ≤ H2 / P ≤ 120.

[0092] Optionally, 10 ≤ 1000R2 / P ≤ 20000, 20 ≤ 1000R2 / P ≤ 20000, 20 ≤ 1000R2 / P ≤ 18000, 20 ≤ 1000R2 / P ≤ 16000, 20 ≤ 1000R2 / P ≤ 14000, 20 ≤ 1000R2 / P ≤ 12000, 20 ≤ 1000R2 / P ≤ 10000, 20 ≤ 1000R2 / P ≤ 8000, 20 ≤ 1000R2 / P ≤ 6000.

[0093] It should be noted that the average particle size G (μm) of the adhesive particles and the pore size P (μm) of the adhesive layer can both be detected by methods and instruments known in the art. For example, the separator can be obtained by disassembling the electrochemical device. The thickness of the adhesive layer and the particle size of the adhesive particles can be measured by the same method as that of the inorganic layer. The pore size of the adhesive layer can be measured by the bubble point method. The separator sample is completely immersed in a liquid to fill the pores with the liquid. Then the sample is placed in a sealed device, and gas is slowly introduced while gradually increasing the gas pressure. Observe the surface of the sample, and when the first bubble appears, record the pressure value at this time, which is the bubble point pressure. According to known parameters such as the surface tension and contact angle of the liquid, the pore size is calculated using relevant formulas.

[0094] In some embodiments, the electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F (μm), and the value ranges of the thickness F of the adhesive layer and the height H2 of the protrusion at the corner are respectively: 0.1 ≤ F ≤ 5, 20 ≤ H2 ≤ 80. For example, F can be 0.1, 0.3, 0.5, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or a range composed of any of the above values, and H2 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range composed of any of the above values; (2) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G (μm). The value ranges of the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner are respectively: 0.1 ≤ G ≤ 2, 20 ≤ H2 ≤ 80. For example, G can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or a range composed of any of the above values, and H2 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range composed of any of the above values; (3) The pore size of the adhesive layer is P (μm). The value ranges of the pore size P of the adhesive layer and the height H2 of the protrusion at the corner are respectively: 0.5 ≤ P ≤ 100, 20 ≤ H2 ≤ 80. For example, P can be 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range composed of any of the above values, and H2 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or a range composed of any of the above values; (4) The pore size of the adhesive layer is P (μm). The value ranges of the pore size P of the adhesive layer and the average radial dimension R2 of the second pattern are respectively: 0.5 ≤ P ≤ 100, 0.3 ≤ R2 ≤ 10. For example, P can be 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range composed of any of the above values, and R2 can be 0.3, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or a range composed of any of the above values.

[0095] Optionally, 0.5 ≤ F ≤ 5, 0.5 ≤ F ≤ 4.5, 0.5 ≤ F ≤ 4, 0.5 ≤ F ≤ 3.5, 0.5 ≤ F ≤ 3, 0.5 ≤ F ≤ 2.5, 0.5 ≤ F ≤ 2.

[0096] 20 ≤ H2 ≤ 78, 20 ≤ H2 ≤ 76, 20 ≤ H2 ≤ 74, 20 ≤ H2 ≤ 72, 20 ≤ H2 ≤ 70, 20 ≤ H2 ≤ 68, 20 ≤ H2 ≤ 66, 20 ≤ H2 ≤ 64, 20 ≤ H2 ≤ 62, 20 ≤ H2 ≤ 60.

[0097] Optionally, 0.1 ≤ G ≤ 1.9, 0.1 ≤ G ≤ 1.8, 0.1 ≤ G ≤ 1.7, 0.1 ≤ G ≤ 1.6, 0.1 ≤ G ≤ 1.5, 0.1 ≤ G ≤ 1.4, 0.1 ≤ G ≤ 1.3, 0.1 ≤ G ≤ 1.2, 0.1 ≤ G ≤ 1.1, 0.1 ≤ G ≤ 1.

[0098] 20 ≤ H2 ≤ 78, 20 ≤ H2 ≤ 76, 20 ≤ H2 ≤ 74, 20 ≤ H2 ≤ 72, 20 ≤ H2 ≤ 70, 20 ≤ H2 ≤ 68, 20 ≤ H2 ≤ 66, 20 ≤ H2 ≤ 64, 20 ≤ H2 ≤ 62, 20 ≤ H2 ≤ 60.

[0099] Optionally, 0.5 ≤ P ≤ 95, 0.5 ≤ P ≤ 90, 0.5 ≤ P ≤ 85, 0.5 ≤ P ≤ 80, 0.5 ≤ P ≤ 75, 0.5 ≤ P ≤ 70, 0.5 ≤ P ≤ 65, 0.5 ≤ P ≤ 60, 0.5 ≤ P ≤ 55, 0.5 ≤ P ≤ 50.

[0100] 20 ≤ H2 ≤ 78, 20 ≤ H2 ≤ 76, 20 ≤ H2 ≤ 74, 20 ≤ H2 ≤ 72, 20 ≤ H2 ≤ 70, 20 ≤ H2 ≤ 68, 20 ≤ H2 ≤ 66, 20 ≤ H2 ≤ 64, 20 ≤ H2 ≤ 62, 20 ≤ H2 ≤ 60.

[0101] Optionally, 0.5 ≤ P ≤ 95, 0.5 ≤ P ≤ 90, 0.5 ≤ P ≤ 85, 0.5 ≤ P ≤ 80, 0.5 ≤ P ≤ 75, 0.5 ≤ P ≤ 70, 0.5 ≤ P ≤ 65, 0.5 ≤ P ≤ 60, 0.5 ≤ P ≤ 55, 0.5 ≤ P ≤ 50.

[0102] 0.5 ≤ R2 ≤ 10, 1 ≤ R2 ≤ 10, 1 ≤ R2 ≤ 9, 1 ≤ R2 ≤ 8, 1 ≤ R2 ≤ 7, 1 ≤ R2 ≤ 6, 1 ≤ R2 ≤ 5, 1 ≤ R2 ≤ 4, 1 ≤ R2 ≤ 3.

[0103] In the above embodiments, when the electrode assembly meets one of the above conditions, the bonding layer and its combination with the convex structure can improve the infiltration ability of the battery cell, enhance the liquid retention ability of the battery, thereby reducing the battery impedance, improving the cycling ability, and further enhancing the heat dissipation ability of the battery cell, achieving improvement in gas generation during high-temperature storage and improvement in thermal box performance.

[0104] In some embodiments, in some specific implementation manners, at least two electrode plates and a separator are wound around a core to form an electrode assembly, where the convex part of the main body protrudes from the main body towards the core, the convex part of the corner protrudes from the corner towards the core or protrudes from the corner away from the core.

[0105] In the above embodiments, when the corner protrusion faces the core, it can occupy a certain space inside the core, making the internal structure of the core more compact, accommodating more active materials or other components within the limited battery space, which is beneficial to improving the energy density of the battery; when the corner protrusion faces away from the core, it can form a buffer between the core and external structures such as the battery housing, reducing the direct collision and friction between the core and the housing when the core is subjected to external impact or vibration, thereby protecting the battery housing and internal structure, reducing the possibility of battery damage caused by external factors, and improving the safety and reliability of the battery.

[0106] In some embodiments, the orthographic projection of the protrusion along the thickness direction of the electrode sheet forms a first figure, and the first figure is a regular circle. In some embodiments, as Figure 3 shown, the distance between two adjacent protrusions of the electrode sheets is L. Among them, the chordal distance between two adjacent protrusions of the electrode sheets is L1 (mm), and the axial distance is L2 (mm), and 1 ≤ L1 + L2 ≤ 20. For example, L1 + L2 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or any range composed of the above arbitrary values.

[0107] It should be noted that the distance between any corner protrusion and the main body protrusion can be detected by using methods and instruments known in the art. For example, it can be directly measured, measured by an optical microscope, etc.

[0108] In some embodiments, the positive electrode sheet may include a positive current collector and a positive active material provided on at least one surface of the positive current collector.

[0109] As an example, the positive current collector has two surfaces opposite to each other in its own thickness direction, and the positive active material is provided on any one or both of the two opposite surfaces of the positive current collector.

[0110] In some embodiments, the negative electrode sheet may include a negative current collector.

[0111] As an example, the negative electrode sheet may include a negative current collector and a negative active material provided on at least one surface of the negative current collector.

[0112] As an example, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative active material is provided on any one or both of the two opposite surfaces of the negative current collector.

[0113] In some embodiments, the present application does not particularly limit the type of the separator, and any well-known porous separator with good chemical stability and mechanical stability can be selected.

[0114] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be coated on the surface of the separator.

[0115] As an example, multiple positive electrode plates and multiple negative electrode plates can be respectively provided, and the multiple positive electrode plates and the multiple negative electrode plates are alternately stacked.

[0116] As an example, multiple positive electrode plates can be provided, and the negative electrode plate is folded to form multiple stacked folding segments, and a positive electrode plate is clamped between adjacent folding segments.

[0117] As an example, both the positive electrode plate and the negative electrode plate are folded to form multiple stacked folding segments.

[0118] As an example, multiple separators can be provided and are respectively arranged between any adjacent positive electrode plates or negative electrode plates.

[0119] In some embodiments, the electrode assembly is provided with electrode tabs, and the electrode tabs can conduct current out of the electrode assembly. The electrode tabs include positive electrode tabs and negative electrode tabs.

[0120] In a second aspect, an electrochemical device includes: a housing and at least one electrode assembly of the first aspect, and the electrode assembly is disposed inside the housing.

[0121] In the embodiments of the present application, the electrochemical device can be a secondary battery cell, and the secondary battery cell refers to a battery cell that can activate the active material and continue to be used by charging after the battery cell discharges.

[0122] The secondary battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present application do not limit this.

[0123] The secondary battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0124] In some embodiments, the secondary battery cell can further include an electrolyte, and the electrolyte plays a role in conducting ions between the positive and negative electrodes. The present application does not specifically limit the type of the electrolyte, and it can be selected according to requirements. The electrolyte can be liquid, gel-like or solid.

[0125] Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0126] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro bis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0127] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0128] In some embodiments, the electrolyte can also optionally include additives. For example, the additives can include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, additives that improve the low-temperature performance of the battery cell, and the like.

[0129] In some embodiments, the secondary battery cell can include a housing. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum plastic film, etc.

[0130] In some embodiments, the housing can be a sealed structure or a non-sealed structure.

[0131] As an example, when the housing is a non-sealed structure, the housing serves to protect the electrode assembly, and a sealed bag can also be included between the housing and the electrode assembly. The sealed bag is used to encapsulate the electrode assembly and the electrolyte. Specifically, the sealed bag can be a bag-shaped insulating member or an aluminum plastic film. When the housing is a sealed structure, it is used to encapsulate components such as the electrode assembly and the electrolyte.

[0132] In some embodiments, the housing includes an end cap and a housing body. The housing body is provided with an opening, and the end cap covers the opening. The housing body can be provided with one or more openings. One or more end caps can also be provided.

[0133] In some embodiments, at least one electrode terminal is provided on the outer casing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab or indirectly connected to the tab through a current collector member. The electrode terminal can be provided on the end cap or on the casing.

[0134] Embodiments of the present application also provide an electronic device including the above-described electrochemical device. The electronic device of the embodiments of the present application is not particularly limited, and it can be any electronic device known in the prior art. In some embodiments, the electronic device may include, but is not limited to, a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable telephone, a portable facsimile machine, a portable copier, a portable printer, a headset stereo earphone, a video recorder, a liquid crystal television, a portable cleaner, a portable CD player, a minidisc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power source, a motor, an automobile, a motorcycle, a moped, a bicycle, a lighting fixture, a toy, a game machine, a clock, a power tool, a flash, a camera, a large household battery, and a lithium-ion capacitor, etc.

[0135] Embodiment

[0136] The following embodiments more specifically describe the content disclosed in the present application. These embodiments are only for illustrative purposes, because various modifications and changes within the scope of the content disclosed in the present application are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and all instruments used in the embodiments are commercially available.

[0137] In the embodiments and comparative examples of the present application, lithium-ion batteries are prepared by the following method and the performance of the lithium-ion batteries is tested:

[0138] Embodiment 1-1

[0139] I. Preparation method of lithium-ion battery

[0140] (1) Preparation of positive electrode sheet

[0141] Lithium cobaltate LiCoO2 as the positive electrode active material, conductive carbon black as the conductive agent, and polyvinylidene fluoride PVDF as the binder are dissolved in an N-methylpyrrolidone NMP solution in a weight ratio of 97.9:0.9:1.2 to form a positive electrode slurry. An aluminum foil with a thickness of 9 μm is used as the positive electrode current collector, and the positive electrode slurry is coated on the positive electrode current collector. After drying, cold pressing, and cutting, a positive electrode sheet is obtained. The compaction density of the positive electrode active material layer of the positive electrode sheet is 4.2 g / cm3 。

[0142] (2) Preparation of the negative electrode sheet

[0143] The artificial graphite as the negative active material, styrene-butadiene rubber (SBR) as the binder, and sodium carboxymethyl cellulose (CMC) as the thickener were dissolved in deionized water in a weight ratio of 97.4:1.4:1.2 to form a negative electrode slurry. A copper foil with a thickness of 10 μm was used as the negative electrode current collector, and the negative electrode slurry was coated on the negative electrode current collector, dried, cold-pressed, and cut to obtain the negative electrode sheet. The compaction density of the negative active material layer of the negative electrode sheet was 1.8 g / cm 3 。

[0144] In the following examples and comparative examples, the negative electrode sheet has a main body protrusion and a corner protrusion.

[0145] (3) Preparation of the separator

[0146] The separator substrate was polyethylene (PE) with a thickness of 5 μm. An aluminum oxide ceramic layer with a thickness of 2 μm was coated on one side of the separator substrate. Finally, a binder of polyvinylidene fluoride (PVDF) with a coating amount of 2.5 mg / 1540.25 mm² was coated on both sides of the separator substrate coated with a single-layer ceramic layer, and then dried to form a bonding layer. The porosity of the bonding layer of the separator was 39%.

[0147] (4) Preparation of the electrolyte

[0148] In an environment with a water content of less than 10 ppm, ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl propionate (EP), and propyl propionate (PP) were mixed evenly in a mass ratio of 1:1:1:1:1. Then, the electrolyte salt LiPF6 was dissolved in the above non-aqueous solvent and mixed evenly to form an electrolyte. Among them, based on the mass of the electrolyte, the mass percentage content of LiPF6 was 12.5%.

[0149] (5) Assembly of the lithium-ion battery

[0150] The positive electrode sheet equipped with a positive electrode tab, the separator, and the negative electrode sheet equipped with a negative electrode tab were stacked in sequence. The separator was placed between the positive electrode sheet and the negative electrode sheet to play a role in isolation, and then wound to obtain an electrode assembly. The electrode assembly was placed in an outer packaging aluminum-plastic film, dehydrated at 80 °C, then the above electrolyte was injected and sealed. After processes such as formation, degassing, and edge trimming, a lithium-ion battery was obtained. The test methods for the various parameters of each embodiment of the present application are described below.

[0151] II. Performance testing of the lithium-ion battery

[0152] (1) Cycle testing and lithium plating testing

[0153] Ambient temperature cycling test: In an environment of 25°C, the electrode assembly is charged at a constant current of 3C to the full charge voltage (the maximum battery design voltage is 4.5V), then charged at a constant voltage at the maximum voltage until the current is 0.02C, and then discharged at a constant current of 0.7C until the final voltage is 3.0V. Record the discharge capacity of the first cycle. Then repeat the above conditions and steps for 1000 charge and discharge cycles, and record the discharge capacity of the lithium-ion battery after 1000 charge and discharge cycles.

[0154] After testing at 25°C and after 1000 charge and discharge cycles, when the battery is in the fully charged state (the maximum battery design voltage is 4.5V), disassemble it and observe whether there is lithium deposition at the negative electrode interface / tab / protective glue. The judgment criterion for the presence or absence of lithium deposition is: the lithium deposition area is greater than 1 square millimeter and appears in ≥30% of the layers.

[0155] (3)Winding yield test

[0156] In an integrated winding machine, the separator is wound between two polar plates with opposite polarities (the positive electrode plate and the negative electrode plate) to form an electrode assembly. Use an X-Ray device to measure the distance M (M>0.1mm is qualified) that the edge of the negative electrode plate of the electrode assembly exceeds the edge of the positive electrode plate in the width direction of the positive electrode plate. Continuously prepare samples, count the total number of samples T (the total number is 100), and the number of qualified products N;

[0157] Winding yield = N / T×100%.

[0158] (4)Test method for average radial dimension R and height H

[0159] Use a scanning electron microscope (SEM) measurement method to measure the polar plate. Put the polar plate sample into the scanning electron microscope, and obtain a high-resolution image of the convex structure through electron beam scanning. In the SEM image, an image processing software can be used to draw a measurement line along the height direction of the convex structure, and calculate the height of the convex structure according to the pixel information of the image and the known magnification. Similarly, in the SEM image, measure the diameter of the convex structure through the image processing software, and obtain the average radial dimension by averaging three values at three positions. It can also be obtained by measuring with a VR series shape profile measuring microscope.

[0160] Examples 1-2 to 1-12, Comparative Examples 1-1 and 1-2

[0161] Examples 1-2 to 1-12, Comparative Examples 1-1 and 1-2 are different from Example 1-1 in that the height H1 of the protrusion of the main body, the diameter R1 of the protrusion of the main body, H1 / 1000R1, the height H2 of the protrusion of the corner, the diameter R2 of the protrusion of the corner, H2 / 1000R2, and the value of H1 / 1000R1 - H2 / 1000R2 are different. For details, see Table 1.

[0162] Table 1

[0163]

[0164] According to Table 1, compared with Comparative Example, the retention rate of charge and discharge cycles for 1000 cycles at 25°C, the lithium deposition during cycling, and the winding excellent rate of each example are all improved. When the protrusion of the main body and the protrusion of the corner in the electrode assembly satisfy -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0165] According to Examples 1-3 to 1-6, when -0.015 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0083, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0166] Examples 2-1 to 2-9

[0167] Examples 2-1 to 2-9 are different from Example 1-1 in that the thickness D of the inorganic layer, the height H2 of the protrusion of the corner, and H2 / D of Examples 2-1 to 2-9 are specially set. For details, see Table 2.

[0168] Table 2

[0169]

[0170] According to Table 2, when the height H2 of the protrusion of the corner acts synergistically with the thickness D of the inorganic layer, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0171] According to Examples 2-1 to 2-9, when 3.3 ≤ H2 / D ≤ 160, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0172] On this basis, according to Examples 2-3 to 2-5, when 6.7 ≤ H2 / D ≤ 60, the lithium-ion battery has more excellent cycling performance and the electrode assembly has more excellent winding excellent rate.

[0173] Examples 3-1 to 3-10

[0174] Examples 3-1 to 3-10 are different from Example 1-1 in that the average particle size E of the inorganic particles in the inorganic layer, the height H2 of the protrusion at the corner, and H2 / E of Examples 3-1 to 3-10 are specially set. For details, see Table 3.

[0175] Table 3

[0176]

[0177] According to Table 3, when the height H2 of the protrusion at the corner acts in synergy with the average particle size E of the inorganic particles in the inorganic layer, the lithium-ion battery has better cycling performance and the electrode assembly has a winding excellent rate.

[0178] According to Examples 3-1 to 3-10, when 10 ≤ H2 / E ≤ 800, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0179] On this basis, according to Examples 3-3 to 3-5, when 20 ≤ H2 / E ≤ 180, the ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0180] Examples 4-1 to 4-9

[0181] Examples 4-1 to 4-9 are different from Example 1-1 in that the thickness F of the adhesive layer, the height H2 of the protrusion at the corner, and H2 / F of Examples 4-1 to 4-9 are different. For details, see Table 4.

[0182] Table 4

[0183]

[0184] According to Table 4, when the height H2 of the protrusion at the corner acts in synergy with the thickness F of the adhesive layer, the lithium-ion battery has better cycling performance and the electrode assembly has a winding excellent rate.

[0185] According to Example 1-1 and Examples 4-1 to 4-9, when 4 ≤ H2 / F ≤ 800, the lithium-ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0186] On this basis, according to Examples 4-3 to 4-5, when 10 ≤ H2 / F ≤ 120, the ion battery has better cycling performance and the electrode assembly has better winding excellent rate.

[0187] Examples 5-1 to 5-9

[0188] Examples 5-1 to 5-9 are different from Example 1-1 in that the average particle size G of the bonding particles of the bonding layer, the heights H2 of the protrusions at the corners, and H2 / G in Examples 5-1 to 5-9 are different. For details, see Table 5.

[0189] Table 5

[0190]

[0191] According to Table 5, when the height H2 of the protrusion at the corner and the average particle size G of the bonding particles of the bonding layer act synergistically, the lithium-ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0192] According to Example 1-1 and Examples 5-1 to 5-9, when 10 ≤ H2 / G ≤ 800, the lithium-ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0193] On this basis, according to Examples 5-3 to 5-5, when 20 ≤ H2 / G ≤ 600, the ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0194] Examples 6-1 to 6-9

[0195] Examples 6-1 to 6-9 are different from Example 1-1 in that the pore size P of the bonding layer, the height H2 of the protrusion at the corner, the diameter R2 of the protrusion at the corner, H2 / P, and 1000R2 / P in Examples 6-1 to 6-9 are different. For details, see Table 6.

[0196] Table 6

[0197]

[0198] According to Table 6, when the height H2 and diameter R2 of the protrusion at the corner and the pore size P of the bonding layer act synergistically, the lithium-ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0199] According to Example 1-1 and Examples 6-1 to 6-9, when 0.2 ≤ H2 / P ≤ 160 and 3 ≤ 1000R2 / P ≤ 20000, the lithium-ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0200] On this basis, according to Examples 6-2 to 6-4, when 0.4 ≤ H2 / P ≤ 120 and 20 ≤ 1000R2 / P ≤ 6000, the ion battery has better cycling performance and the electrode assembly has a better winding yield.

[0201] Although the present application has been described with reference to preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly, characterized in that, Comprising: At least two electrode plates and a separator, the separator being disposed between two adjacent electrode plates; At least one of the electrode plates includes a main body portion and corner portions located on both sides of the main body portion. The main body portion includes a plurality of main body portion protrusions, the cross-section of the main body portion protrusion along the thickness direction of the electrode plate is arc-shaped, the vertical height from the vertex of the upper surface of the main body portion protrusion to the upper surface of the area of the electrode plate without protrusions is H1 μm, the orthographic projection of the main body portion protrusion along the thickness direction of the electrode plate forms a first pattern, the average radial dimension of the first pattern is the average value R1 mm of the longest diameters of the plurality of first patterns. The corner portion includes a plurality of corner portion protrusions, the cross-section of the corner portion protrusion along the thickness direction of the electrode plate is arc-shaped, the vertical height from the vertex of the upper surface of the corner portion protrusion to the upper surface of the area of the electrode plate without protrusions is H2 μm, the orthographic projection of the corner portion protrusion along the thickness direction forms a second pattern, the average radial dimension of the second pattern is the average value R2 mm of the longest diameters of the plurality of second patterns, and it satisfies: -0.2665 ≤ H1 / 1000R1 - H2 / 1000R2 ≤ 0.0131; The separator includes a base film and an adhesive layer, the adhesive layer is disposed on both sides of the base film, the thickness of the adhesive layer is F μm, and the electrode assembly satisfies: 4 ≤ H2 / F ≤ 800.

2. The electrode assembly according to claim 1, characterized in that, Satisfying: 0.0005 ≤ H1 / 1000R1 ≤ 0.0151, and / or, satisfying: 0.002 ≤ H2 / 1000R2 ≤ 0.

267.

3. The electrode assembly according to claim 1, characterized in that Satisfying: 0.015 ≤ H1 / 1000R1 ≤ 0.025, and / or, satisfying: 0.0167 ≤ H2 / 1000R2 ≤ 0.

025.

4. The electrode assembly according to claim 1, wherein The electrode assembly satisfies at least one of the following: （1）5≤H1≤35； （2）20≤H2≤80； （3）0.3≤R1≤10； （4）0.3≤R2≤10。 5. The electrode assembly according to claim 1, wherein The separator further includes an inorganic layer, the inorganic layer is disposed between the base film and the adhesive layer, the thickness of the inorganic layer is D μm, and the electrode assembly satisfies: 3.3 ≤ H2 / D ≤ 160.

6. The electrode assembly according to claim 5, wherein The electrode assembly satisfies: 6.7 ≤ H2 / D ≤ 60.

7. The electrode assembly according to claim 1, characterized in that, The separator further includes an inorganic layer, the inorganic layer is disposed between the base film and the adhesive layer, the inorganic layer includes inorganic particles, the average particle size of the inorganic particles is E μm, and the electrode assembly satisfies: 10 ≤ H2 / E ≤ 800.

8. The electrode assembly according to claim 7, wherein The value ranges of the thickness D of the inorganic layer and the height H2 of the corner portion protrusion are respectively: 1 ≤ D ≤ 3, 20 ≤ H2 ≤ 60.

9. The electrode assembly according to claim 1, characterized in that, The separator further includes an inorganic layer, the inorganic layer is disposed between the base film and the adhesive layer, the inorganic layer includes inorganic particles, the average particle size of the inorganic particles is E μm, and the electrode assembly satisfies: 10 ≤ H2 / E ≤ 800.

10. The electrode assembly according to claim 9, wherein, The electrode assembly satisfies: 20 ≤ H2 / E ≤ 180.

11. The electrode assembly according to claim 1, wherein The separator membrane further includes an inorganic layer disposed between the base film and the adhesive layer. The inorganic layer includes inorganic particles, and the average particle size of the inorganic particles is E μm. The value ranges of the average particle size E of the inorganic particles and the height H2 of the protrusion at the corner are: 0.1 ≤ E ≤ 2, 20 ≤ H2 ≤ 80.

12. The electrode assembly according to claim 11, wherein The value ranges of the average particle size E of the inorganic particles and the height H2 of the protrusion at the corner are: 0.3 ≤ E ≤ 1, 20 ≤ H2 ≤ 60.

13. The electrode assembly according to any one of claims 1-12, characterized in that, The electrode assembly satisfies at least one of the following: (1) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G μm, 10 ≤ H2 / G ≤ 800; (2) The pore size of the adhesive layer is P μm, 0.2 ≤ H2 / P ≤ 160; (3) The pore size of the adhesive layer is P μm, 3 ≤ 1000R2 / P ≤ 20000.

14. The electrode assembly according to any one of claims 1 to 12, characterized in that, The electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F μm, 10 ≤ H2 / F ≤ 120; (2) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G μm, 20 ≤ H2 / G ≤ 600; (3) The pore size of the adhesive layer is P μm, 0.4 ≤ H2 / P ≤ 120; (4) The pore size of the adhesive layer is P μm, 20 ≤ 1000R2 / P ≤ 6000.

15. The electrode assembly according to any one of claims 1-12, characterized in that, The electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F μm, and the value ranges of the thickness F of the adhesive layer and the height H2 of the protrusion at the corner are: 0.1 ≤ F ≤ 5, 20 ≤ H2 ≤ 80; (2) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G μm, and the value ranges of the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner are: 0.1 ≤ G ≤ 2, 20 ≤ H2 ≤ 80; (3) The pore size of the adhesive layer is P μm, and the value ranges of the pore size P of the adhesive layer and the height H2 of the protrusion at the corner are: 0.5 ≤ P ≤ 100, 20 ≤ H2 ≤ 80; (4) The pore size of the adhesive layer is P μm, and the value ranges of the pore size P of the adhesive layer and the average radial dimension R2 of the second pattern are: 0.5 ≤ P ≤ 100, 0.3 ≤ R2 ≤ 10.

16. The electrode assembly according to any one of claims 1 to 12, characterized in that, The electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F μm, and the value ranges of the thickness F of the adhesive layer and the height H2 of the protrusion at the corner are: 0.5 ≤ F ≤ 2, 20 ≤ H2 ≤ 60; (2) The adhesive layer includes adhesive particles, and the average particle size of the adhesive particles is G μm, and the value ranges of the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner are: 0.1 ≤ G ≤ 1, 20 ≤ H2 ≤ 60; (3) The pore size of the adhesive layer is P μm, and the value ranges of the pore size P of the adhesive layer and the height H2 of the protrusion at the corner are: 0.5 ≤ P ≤ 50, 20 ≤ H2 ≤ 60; (4) The pore size of the adhesive layer is P μm, and the value ranges of the pore size P of the adhesive layer and the average radial dimension R2 of the second pattern are respectively: 0.5 ≤ P ≤ 50, 1 ≤ R2 ≤ 3.

17. The electrode assembly according to any one of claims 1-12, characterized in that, The separator includes a base film and an inorganic layer. The at least two electrode tabs and the separator are wound around a core to form the electrode assembly. The protrusion of the main body portion protrudes from the main body portion toward the core. The protrusion of the corner portion protrudes from the corner portion toward the core or protrudes from the corner portion away from the core.

18. An electrochemical device, characterized in that, It includes: a housing and at least one electrode assembly according to any one of claims 1-17, and the electrode assembly is disposed inside the housing.

19. An electronic device, characterized in that, The electronic device includes the electrochemical device according to claim 18 above.

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