Electrode assembly, electrochemical device, and electronic device

Abstract

The invention discloses an electrode assembly, an electrochemical device and an electronic device. The electrode assembly provided by the embodiment of the invention comprises at least two pole pieces and an isolating membrane, wherein the isolating membrane is arranged between the two adjacent pole pieces; at least one pole piece comprises a main body part and a corner part located on the peripheral side of the main body part, the main body part comprises a plurality of main body part protrusions, the corner part comprises a plurality of corner part protrusions, the height of the corner part protrusions is H2 (mu m), orthographic projections of the corner part protrusions in the thickness direction form a second pattern, and the average radial size of the second pattern is R2 (mm); the isolating membrane comprises a base membrane and an inorganic layer, at least one side of the base membrane is coated with the inorganic layer, the thickness of the inorganic layer is D ([mu] m), and the electrode assembly meets the condition that H2 / D is larger than or equal to 3.3 and smaller than or equal to 160. According to the electrode assembly provided by the invention, the interlayer gap between the diaphragm and the pole piece is increased, so that the electrolyte can enter the naked battery core more easily, and the battery core infiltration effect is improved.

Description

[0001] This application is a divisional application based on the invention with application number 202510223462.8, application date February 27, 2025, applicant Ningde New Energy Technology Co., Ltd., and invention name “Electrode assembly, electrochemical device and electronic device”. Technical Field

[0002] 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

[0003] Nowadays, 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 shell installation. However, in this case, the wound battery cells after hot pressing will make it difficult for the electrolyte to enter the interior of the bare battery cells, thereby affecting the battery cell cycle performance. Summary of the Invention

[0004] 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 diaphragm and the electrode piece, making it easier for the electrolyte to enter the interior of the bare battery cell, thereby improving the battery cell wetting effect.

[0005] In the first aspect, an embodiment of the present application provides an electrode assembly, comprising: at least two pole pieces and an isolation membrane, the isolation membrane being arranged between two adjacent pole pieces; at least one pole piece comprising a main body and a corner portion located on the peripheral side of the main body, the main body comprising a plurality of main body protrusions, the corner portion comprising a plurality of corner protrusions, the height of the corner protrusions being H2 (μm), the orthographic projection of the corner protrusions along the thickness direction constituting a second figure, the average radial dimension of the second figure being R2 (mm); the isolation membrane comprising a base film and an inorganic layer, the inorganic layer being coated on at least one side of the base film, the thickness of the inorganic layer being D (μm), and the electrode assembly satisfies: 3.3≤H2 / D≤160.

[0006] According to the embodiments of the present application, the electrode assembly satisfies the following conditions: 3.3 ≤ H2 / D ≤ 160. When the thickness of the inorganic layer and the height H2 of the protrusion at the corner of the electrode assembly meet these conditions, the inorganic layer has good ionic conductivity and can provide a smooth transmission path for lithium ions. A channel is formed between the electrode and the separator to facilitate the flow of electrolyte, ensuring that 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.

[0007] At the same time, the inorganic layer and the raised structure at the corners work together to disperse the stress generated by the electrode to a larger area, avoiding stress concentration, effectively protecting the integrity of the battery's internal structure, and improving the battery's cycle stability.

[0008] In some specific embodiments, the height of the main body protrusion is H1 (μm), and the orthographic projection of the main body protrusion along the thickness direction of the pole piece constitutes a first figure (the orthographic projection in this 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 figure is R1 (mm), and the main body protrusion and the corner protrusion satisfy: -0.25≤H1 / 1000R1-H2 / 1000R2≤0.0131. The average radial dimension in this application is the longest diameter of the first figure formed by the orthographic projection of the protrusion along the thickness direction of the pole piece. In some specific embodiments, the first figure / second figure formed by the orthographic projection is circular, and the average radial dimension is the diameter of the circle.

[0009] In this specific embodiment, the present application regulates the characteristics of the main body protrusion and the corner protrusion, and when H1 / 1000R1-H2 / 1000R2 satisfies: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131, the electrolyte can be more evenly and efficiently penetrated into all parts of the battery cell, greatly improving the infiltration 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 such as ion transmission obstruction and poor interface stability at the weak area interface, further improving the overall performance and stability of the battery cell and the cycle performance of the battery;

[0010] This application focuses on the ratio 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 infiltration effect on the electrode, which in turn affects the cycle performance and also causes serious lithium deposition. Therefore, when H1 / 1000R1-H2 / 1000R2 meets the range limited by this application, the difference between the raised structure in the main area and the raised structure in the corner area can be made to meet the appropriate range, thereby improving the cycle performance of the battery at high current density and alleviating the lithium deposition phenomenon of the electrode after the battery is cycled at high current density, thereby improving the winding quality rate.

[0011] In some specific 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.

[0012] In this specific embodiment, the protrusion of the main body satisfies: 0.0005≤H1 / 1000R1≤0.0151, and / or the protrusion of the corner portion satisfies: 0.002≤H2 / 1000R2≤0.267, which 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.

[0013] In some specific embodiments, the protrusion of the main body satisfies: 0.015≤H1 / 1000R1≤0.025, and / or, the protrusion of the corner portion satisfies: 0.0167≤H2 / 1000R2≤0.025. The protrusion of the main body and the protrusion of the corner portion provide effective support for the isolation membrane, so that the isolation membrane maintains a stable position and shape inside the battery, preventing the isolation membrane from shifting, deforming or damaging during the winding of the electrode assembly or the use of the battery, ensuring that the isolation membrane can normally play its role in isolating the positive and negative electrodes and preventing short circuits, thereby improving the safety and stability of the battery.

[0014] 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.

[0015] In this specific embodiment, the main body protrusion and the corner protrusion meet one of the above conditions. The main body protrusion and the corner protrusion can better improve the electrolyte infiltration effect on the battery cell, further improving the overall performance and stability of the battery cell.

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

[0017] In the above specific embodiment, the electrode assembly satisfies: 6.7≤H2 / D≤60, which can further enhance the strength of the electrode assembly, reduce the problem of diaphragm puncture during battery use, and improve the electrolyte infiltration effect.

[0018] In some specific embodiments, the thickness of the inorganic layer is D (μm), and the thickness D of the inorganic layer and the height H2 of the protrusion at the corner portion are in the range of 0.5≤D≤6, 20≤H2≤80, respectively.

[0019] In the above specific embodiment, 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.

[0020] In some specific embodiments, the thickness D of the inorganic layer and the height H2 of the protrusion at the corner portion are in the range of 1≤D≤3 and 20≤H2≤60, respectively.

[0021] In the above specific embodiment, the synergistic effect of the inorganic layer and the corner protrusions can further enhance the strength of the electrode assembly, further reduce the problem of diaphragm puncture during battery use, and improve the infiltration effect of the electrolyte.

[0022] In some specific embodiments, 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.

[0023] In the above-described specific embodiment, the electrode assembly satisfies the following conditions: 10 ≤ H2 / E ≤ 800. The inorganic particles and the corner protrusions work synergistically to buffer the stress caused by volume changes in the electrode material during battery charging and discharging, reducing the risk of structural damage and pulverization of the electrode material. Furthermore, the synergistic effect of the two optimizes the interface between the electrode and the electrolyte, facilitating charge transfer and reducing charge transfer resistance.

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

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

[0026] In some specific embodiments, the inorganic layer includes inorganic particles, the average particle size of the inorganic particles is E (μm), and the average particle size E of the inorganic particles and the height H2 of the corner protrusion are in the range of 0.1≤E≤2, 20≤H2≤80, respectively.

[0027] In the above specific embodiment, the corner protrusions and the inorganic particles work together to increase the roughness and irregularity of the surface of the electrode assembly, thereby increasing the contact points and contact area between the electrolyte and the electrode. At the same time, the inorganic particles can be filled in the channels formed by the corner protrusions, which on the one hand 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 deeper into the material, thereby improving the electrolyte infiltration effect, improving the battery quality and battery safety.

[0028] In some specific embodiments, the inorganic layer includes inorganic particles, the particle size of the inorganic particles is E, and the average particle size E of the inorganic particles and the height H2 of the protrusions on the corners are in the range of 0.3≤E≤1, 20≤H2≤60, respectively.

[0029] In the above specific embodiment, the corner protrusions and inorganic particles work synergistically to increase the roughness and irregularity of the electrode assembly surface while further improving the microstructure of the channels formed by the inorganic particles filling the corner protrusions, thereby further improving the electrolyte infiltration effect and battery quality and battery safety.

[0030] In some specific embodiments, the isolation film may further include an adhesive layer, the adhesive layer being arranged on both sides of the base film, and the inorganic layer being arranged between the base film and the adhesive layer; the electrode assembly satisfies at least one of the following: (1) the thickness of the adhesive layer is F μm, 4≤H2 / F≤800; (2) the thickness of the adhesive layer is F μm, 10≤H2 / F≤120; (3) 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; (4) 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.

[0031] In the above specific embodiment, when 4≤H2 / F≤800, the corner protrusion cooperates with the adhesive layer to maintain a stable position of the separator inside the battery, reducing the risk of displacement, wrinkling or damage, improving the regularity of the internal structure of the battery, and improving 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 separator, so that the electrolyte fully infiltrates the electrode and the separator, improving the ion transmission efficiency, and thus improving the charge and discharge performance and rate performance of the battery. At the same time, the adhesive layer tightly combines the separator with the corner protrusion and the main body protrusion to form a stable interface, reduce the resistance at the interface, and reduce the energy loss of the battery during charging and discharging.

[0032] In some specific embodiments, the isolation film may further include an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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), 10≤H2 / G≤800, and 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 isolation film, making the bonding between the two tighter and stronger, making the isolation film less likely to shift or fall off inside the battery, and improving the stability of the internal structure of the battery. The corner protrusions and 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 and the isolation film, thereby improving the electrolyte Adsorption and diffusion enable the electrolyte to be more evenly distributed around the electrode and the separator, thereby improving the ion transmission efficiency and thus improving the charge and discharge performance and rate performance of the battery; (2) When the pore size of the adhesive layer is P (μm), 0.2≤H2 / P≤160, and 0.2≤H2 / P≤160, the electrolyte can be more evenly distributed around the electrode and the separator, thereby improving the ion transmission efficiency and thus improving the charge and discharge performance and rate performance of the battery; (3) When the pore size of the adhesive layer is P (μm), 3≤1000R2 / P≤20000, and 3≤1000R2 / P≤20000, the adhesive layer has better flexibility and deformability, more effectively buffers stress, avoids damage to the separator due to local stress concentration, and extends the service life of the separator and the battery.

[0033] In some specific embodiments, the isolation film may further include an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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), 20≤H2 / G≤600; (2) the pore size of the adhesive layer is P (μm), 0.4≤H2 / P≤120; (3) the pore size of the adhesive layer is P (μm), 20≤1000R2 / P≤6000.

[0034] In some specific embodiments, the isolation film may further include an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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 the average particle size G of the adhesive particles and the height H2 of the corner protrusion are in the range of 0.1≤G≤2, 20≤H2≤80; (2) the pore size of the adhesive layer is P (μm), and the pore size P of the adhesive layer and the height H2 of the corner protrusion are in the range of 0.5≤P≤100, 20≤H2≤80; (3) the pore size of the adhesive layer is P (μm), and the pore size P of the adhesive layer and the average radial dimension R2 of the second figure are in the range of 0.5≤P≤100, 0.3≤R2≤10.

[0035] In the above specific embodiment, the electrode assembly meets one of the above conditions, and the combination of the adhesive layer and the protruding structure can improve the wetting ability of the battery cell, enhance the liquid retention capacity of the battery, thereby reducing the battery impedance, improving the cycle capacity, and further enhancing the heat dissipation capacity of the battery cell, achieving improved high-temperature storage gas production and improved hot box performance.

[0036] In some specific embodiments, the isolation film may further include an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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 the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner are in the range of 0.1≤G≤1, 20≤H2≤60; (2) the pore size of the adhesive layer is P (μm), and the pore size P of the adhesive layer and the height H2 of the protrusion at the corner are in the range of 0.5≤P≤50, 20≤H2≤60; (3) the pore size of the adhesive layer is P, and the pore size P of the adhesive layer and the average radial dimension R2 of the second figure are in the range of 0.5≤P≤50, 1≤R2≤3.

[0037] In the above specific embodiment, the electrode assembly meets one of the above conditions, and the combination of the adhesive layer and the protruding structure can improve the wetting ability of the battery cell, enhance the liquid retention capacity of the battery, thereby reducing the battery impedance, improving the cycle capacity, and further enhancing the heat dissipation capacity of the battery cell, achieving improved high-temperature storage gas production and improved hot box performance.

[0038] In some specific embodiments, at least two pole pieces and an isolation film are wound around a winding core to form an electrode assembly, the main body protrusion is formed by the main body protruding toward the winding core, and the corner protrusion is formed by the corner protruding toward the winding core or by the corner protruding away from the winding core.

[0039] In the above specific embodiment, the protrusion of the corner portion toward the roll core can occupy a certain space inside the roll core, making the internal structure of the roll 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 protrusion of the corner portion facing away from the roll core can form a buffer between the roll core and external structures such as the battery shell, reducing the direct collision and friction between the roll core and the shell when subjected to external force impact or vibration, thereby protecting the battery shell and internal structure, reducing the possibility of battery damage due to external factors, and improving the safety and reliability of the battery.

[0040] In a second aspect, an embodiment of the present application provides an electrochemical device, comprising: a housing and at least one electrode assembly according to the first aspect, wherein the electrode assembly is disposed inside the housing.

[0041] 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

[0042] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic structural diagram of an electrode assembly according to one embodiment of the present application;

[0044] Figure 2 This is a schematic structural diagram of a pole piece protrusion according to an embodiment of the present application;

[0045] Figure 3 Schematic diagram of the spacing setting between pole piece protrusions according to an embodiment of the present application.

[0046] In the accompanying drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0047] The embodiments of the present application will be described in detail below. The embodiments of the present application should not be interpreted as limiting the present application.

[0048] As used in this application, the terms "including," "containing," and "comprising" are used in their open, non-limiting sense.

[0049] In addition, amounts, ratios, and other numerical values ​​are sometimes presented herein in a range format. It should be understood that such a range format is used for convenience and brevity and should be interpreted flexibly to include not only the values ​​explicitly specified as limits of the range, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0050] In the detailed description and claims, a list of items connected by the terms "one or more of," "one or more of," "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, 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, 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 contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

[0051] The isolation membrane and two pole pieces are wound multiple times along the length of the pole piece to form an electrode assembly. The length of the pole piece is the direction in which the pole piece is wound, and the width direction is perpendicular to the length. The electrode assembly is flat, and each pole piece includes two main parts and two corner parts, and the two main parts are connected between the two corner parts. Among them, the corners of two adjacent pole pieces are prone to mutual extrusion, and the main part and corner part of each pole piece are also squeezed. Therefore, the corners are the high-incidence areas for extrusion of the electrode assembly. When the corners are squeezed, it is easy to cause problems such as insufficient electrolyte and poor infiltration, which in turn leads to deterioration of the pole piece interface at the corners and even cycle failure.

[0052] 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 diaphragm and the electrode piece, making it easier for the electrolyte to enter the interior of the bare battery cell, thereby improving the battery cell wetting effect.

[0053] The following describes the implementation of the present application in detail.

[0054] Electrode assembly

[0055] In a first aspect, the present invention provides an electrode assembly, such as Figure 1 As shown, the electrode assembly of the embodiment of the present application includes two electrode sheets with opposite polarity and a separator disposed between the two electrode sheets. The length direction (machine direction, MD direction), width direction (transverse direction, TD direction) and thickness direction of the two electrode sheets with opposite polarity are consistent. The separator is disposed between the two electrode sheets with opposite polarity in the thickness direction of the electrode sheets. One of the two electrode sheets with opposite polarity is a positive electrode sheet and the other is a negative electrode sheet. The separator has insulating properties and is used to separate the positive electrode sheet from the negative electrode sheet to prevent short circuits.

[0056] At least one of the two pole pieces is provided with a plurality of pole piece protrusions (also referred to as pole piece protrusions), such as Figure 2 As 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 and corner portions provided at both ends of the main body, the main body includes a plurality of main body protrusions (also referred to as main body protrusions), the height of the main body protrusion is H1 (μm), the orthographic projection of the main body protrusion along the thickness direction of the pole piece constitutes a first figure, and the average radial dimension of the first figure is R1 (mm), the corner portion includes a plurality of corner protrusions (also referred to as corner protrusions), the height of the corner protrusion is H2 (μm), the orthographic projection of the corner protrusion along the thickness direction constitutes a second figure, and the average radial dimension of the second figure is R2 (mm). In the pole piece, the main body protrusion and the corner protrusion satisfy: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131;

[0057] The isolation film includes a base film and an adhesive layer. The adhesive layer is arranged on both sides of the base film. The thickness of the adhesive layer is F (μm). The electrode assembly meets: 4≤H2 / F≤800.

[0058] 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 consisting of any of the above values.

[0059] 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 consisting of any of the above values.

[0060] Optional, -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.

[0061] 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.

[0062] According to the present application, by regulating the characteristics of the main body protrusion and the corner protrusion, when H1 / 1000R1-H2 / 1000R2 satisfies: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131, the electrolyte can be more evenly and efficiently penetrated into all parts of the battery cell, greatly improving the infiltration 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 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.

[0063] 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 layer and the layer 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 infiltration effect on the electrode, which in turn affects the cycle performance and also causes serious lithium deposition. Therefore, when H1 / 1000R1-H2 / 1000R2 meets the range limited by this application, the difference between the raised structure in the main area and the raised structure in the corner area can be made to meet the appropriate range, thereby improving the cycle performance of the battery at high current density and alleviating the lithium deposition phenomenon of the electrode after the battery is cycled at high current density, thereby improving the winding quality rate.

[0064] On this basis, the corner protrusions 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 thus 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 corner protrusions and the main body protrusions to form a stable interface, reduce the resistance at the interface, and reduce the energy loss of the battery during charging and discharging.

[0065] The above is only an exemplary introduction. This 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.

[0066] 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 scanning electron microscope (SEM) measurement method is used to place the pole piece sample in a scanning electron microscope, and a high-resolution image of the protruding structure is 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 image processing software to obtain the radius. It can also be measured using a VR series shape profile measurement microscope. The electrochemical device can be disassembled to obtain the separator. This separator can then be sliced ​​using a scanning electron microscope (SEM) to produce a flat cross-sectional sample. The sample is placed in the SEM, and appropriate accelerating voltage and scanning parameters are selected to obtain a high-resolution cross-sectional image. The thickness F of the adhesive layer can be measured directly from the image using the SEM's built-in image processing software.

[0067] 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.

[0068] 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 consisting of any of the above values.

[0069] 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 consisting of any of the above values.

[0070] Optional, 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.

[0071] Optional, 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≤H 2 / 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.

[0072] In the above 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. The protrusion of the main body and the protrusion of the corner portion provide effective support for the isolation membrane, so that the isolation membrane maintains a stable position and shape inside the battery, preventing the isolation membrane from shifting, deforming or damaging during the winding of the electrode assembly or the use of the battery, ensuring that the isolation membrane can normally play the role of isolating the positive and negative electrodes and preventing short circuits, thereby improving the safety and stability of the battery.

[0073] 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 consisting 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 consisting 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 consisting 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 consisting of any of the above values.

[0074] In the above embodiments, when the electrode assembly meets any of the above conditions, the protrusions on the main body and the corners can better improve the wetting effect of the electrolyte on the battery cell, further improving the overall performance and stability of the battery cell.

[0075] In some embodiments, the separator may further include an inorganic layer disposed between the base film and the adhesive layer. The thickness of the inorganic layer is D (μm). The electrode assembly satisfies the following relationship: 3.3 ≤ H2 / D ≤ 160. For example, H2 / D may be 3.3, 5, 8, 10, 20, 30, 40, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150, 160, or any range thereof.

[0076] Optional, 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.

[0077] In the above embodiment, the electrode assembly satisfies the following conditions: 3.3 ≤ H2 / D ≤ 160. When the thickness of the inorganic layer and the height H2 of the protrusion at the corner of the electrode assembly meet these conditions, the inorganic layer has excellent ionic conductivity, providing a smooth transmission path for lithium ions. A channel is formed between the electrode and the separator, which facilitates the flow of electrolyte, ensuring that lithium ions in the electrolyte can quickly reach the surface of the inorganic layer. The combination of the two makes the transfer of lithium ions between the electrode and the electrolyte more efficient, thereby improving the battery's charge and discharge rates.

[0078] At the same time, the inorganic layer and the corner protrusions work together to disperse the stress generated by the electrode to a larger area, avoiding stress concentration, effectively protecting the integrity of the battery's internal structure, and improving the battery's cycle stability.

[0079] It should be noted that the thickness D (μm) of the inorganic layer can be measured using methods and instruments known in the art. For example, the electrochemical device can be disassembled to obtain an isolating membrane, which can then be sliced ​​using a scanning electron microscope (SEM) to produce a flat cross-sectional sample. The sample is placed in an SEM device, and appropriate acceleration voltage and scanning parameters are selected to obtain a high-resolution cross-sectional image. The thickness of the inorganic layer can be measured directly from the image using the SEM's built-in image processing software.

[0080] In some embodiments, the isolation 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). The thickness D of the inorganic layer and the height H2 of the corner protrusion are in the range of 0.5 ≤ D ≤ 6 and 20 ≤ H2 ≤ 80, respectively. For example, D may be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, or any range thereof. H2 may be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or any range thereof.

[0081] 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.

[0082] 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.

[0083] In the above embodiment, the inorganic layer and the corner protrusions work together to effectively enhance the strength of the electrode assembly, reduce the problem of diaphragm puncture during battery use, and improve the electrolyte infiltration effect.

[0084] In some embodiments, the separator may further include an inorganic layer disposed between the base film and the adhesive layer. The inorganic layer may include inorganic particles having a particle size of E (μm). The electrode assembly satisfies the following relationship: 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 any range thereof.

[0085] 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.

[0086] In the above embodiment, the electrode assembly satisfies the following conditions: 10 ≤ H2 / E ≤ 800. The inorganic particles and the corner protrusions work synergistically to buffer the stress caused by volume changes in the electrode material during battery charging and discharging, reducing the risk of structural damage and pulverization of the electrode material. Furthermore, the synergistic effect of the two optimizes the interface between the electrode and the electrolyte, facilitating charge transfer and reducing charge transfer resistance.

[0087] 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 electrochemical device can be disassembled to obtain an isolation membrane, and the isolation membrane sample containing the inorganic layer can be dried, fixed, and subjected to other treatments using a scanning electron microscope (SEM) measurement method. The sample is then 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.

[0088] In some embodiments, the isolation film may further include an inorganic layer, the inorganic layer being disposed between the base film and the adhesive layer, the inorganic layer including inorganic particles, the particle size of the inorganic particles being E (μm), the average particle size E of the inorganic particles and the height H2 of the protrusions at the corners being in the range of 0.1 ≤ E ≤ 2, 20 ≤ H 2 ≤ 80, respectively. For example, E may 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 consisting of any of the above values. H 2 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.

[0089] Optional, 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.

[0090] 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.

[0091] In the above embodiment, the corner protrusions and the inorganic particles work together to increase the roughness and irregularity of the surface of the electrode assembly, thereby increasing the contact points and contact area between the electrolyte and the electrode. At the same time, the inorganic particles can be filled in the channels formed by the corner protrusions, which on the one hand 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 deeper into the material, thereby improving the electrolyte infiltration effect, improving the battery quality and battery safety.

[0092] In some embodiments, the electrode assembly satisfies at least one of the following conditions: (1) the bonding layer includes bonding particles, the average particle size of the bonding particles is G (μm), 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 consisting of any of the above values, when 10≤H2 / G≤800, the bonding particles in the bonding layer can fill the tiny gaps between the protrusions on the corner portion and the protrusions on the main body and the isolation film, The bonding between the two is made tighter and firmer, so that the separator is not easily displaced or detached inside the battery, and the stability of the internal structure of the battery is improved. The protrusions on the corners and the protrusions on the main body and the adhesive particles on the adhesive layer work together to optimize the transmission path of the electrolyte between the electrode and the separator, improve the adsorption and diffusion of the electrolyte, and make the electrolyte more evenly distributed around the electrode and the separator, thereby improving the ion transmission efficiency and thus improving the charge and discharge performance and rate performance of the battery; (2) The pore size of the adhesive layer is P (μm), 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 any range of the above values, when 0.2≤H2 / P≤160, the electrolyte can be more evenly distributed around the electrode and the separator, thereby improving the ion transfer efficiency and thus improving the charge and discharge performance and rate performance of the battery; (3) the pore size of the adhesive layer is P (μm), 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 consisting of any of the above values, when 3≤1000R2 / P≤20000, the adhesive layer has better flexibility and deformability, more effectively buffers stress, avoids damage to the isolation membrane due to local stress concentration, and extends the service life of the isolation membrane and the battery.

[0093] Optional, 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.

[0094] Optional, 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.

[0095] Optional, 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.

[0096] It should be noted that the average particle size G (μm) of the bonding particles and the pore size P (μm) of the bonding 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 thickness of the bonding layer and the particle size of the bonding particles can be measured using the same method as the inorganic layer. The pore size of the bonding layer can be measured using the bubble point method. The isolation membrane sample is completely immersed in the liquid so that the pores are filled with liquid. The sample is then placed in a sealed device, and gas is slowly introduced to gradually increase 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. Based on known parameters such as the liquid surface tension and contact angle, the pore size is calculated using relevant formulas.

[0097] 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 corner protrusion are: 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, the average particle size of the adhesive particles is G (μm), the average particle size G of the adhesive particles and the height H2 of the corner protrusion are in the range of 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 any range thereof, and H2 can be 20, 25, 30, 35, 40 , 45, 50, 55, 60, 65, 70, 75, 80, or any range thereof; (3) the pore size of the adhesive layer is P (μm), and the pore size P of the adhesive layer and the height H2 of the protrusion at the corner portion are in the range of 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 any range thereof, and H2 can be 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 , 75, 80, or a range consisting of any of the above values; (4) the pore size of the adhesive layer is P (μm), and the pore size P of the adhesive layer and the average radial dimension R2 of the second pattern are in the range of 0.5≤P≤100, 0.3≤R2≤10, respectively. For example, P can be 0.5, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, or a range consisting 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 consisting of any of the above values.

[0098] Optional, 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.

[0099] 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.

[0100] Optional, 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.

[0101] 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.

[0102] Optional, 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.

[0103] 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.

[0104] Optional, 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.

[0105] 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.

[0106] In the above embodiment, the electrode assembly meets one of the above conditions, and the combination of the adhesive layer and the protruding structure can improve the wetting ability of the battery cell, enhance the liquid retention capacity of the battery, thereby reducing the battery impedance, improving the cycle capacity, and further enhancing the heat dissipation capacity of the battery cell, achieving improved high-temperature storage gas production and improved hot box performance.

[0107] In some embodiments, in some specific implementations, at least two pole pieces and an isolation membrane are wound around a winding core to form an electrode assembly, the main body protrusion is formed by the main body protruding toward the winding core, and the corner protrusion is formed by the corner protruding toward the winding core or by the corner protruding away from the winding core.

[0108] In the above embodiment, the protrusion of the corner portion toward the roll core can occupy a certain space inside the roll core, making the internal structure of the roll 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 protrusion of the corner portion facing away from the roll core can form a buffer between the roll core and external structures such as the battery shell, reducing the direct collision and friction between the roll core and the shell when subjected to external force impact or vibration, thereby protecting the battery shell and internal structure, reducing the possibility of battery damage due to external factors, and improving the safety and reliability of the battery.

[0109] In some embodiments, the orthographic projection of the protrusion along the thickness direction of the pole piece forms a first figure, and the first figure is a regular circle. Figure 3 As shown, the spacing between two adjacent pole piece protrusions is L, wherein the chordal spacing between two adjacent pole piece protrusions is L1 (mm), and the axial spacing is L2 (mm), 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 a range consisting of any of the above values.

[0110] It should be noted that the distance between any corner protrusion and the main body protrusion can be measured using methods and instruments known in the art, for example, by direct measurement or measurement using an optical microscope.

[0111] In some embodiments, the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0112] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0113] In some embodiments, the negative electrode sheet may include a negative current collector.

[0114] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0115] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0116] In some embodiments, the present application has no particular limitation on the type of isolation membrane, and any known isolation membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0117] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. 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 separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. The surface of the separator can also be coated with an inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating.

[0118] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0119] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0120] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0121] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0122] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0123] In a second aspect, an electrochemical device includes: a housing and at least one electrode assembly according to the first aspect, wherein the electrode assembly is disposed inside the housing.

[0124] In the embodiment of the present application, the electrochemical device may be a secondary battery cell. A secondary battery cell refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0125] Secondary battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc., which are not limited in the embodiments of the present application.

[0126] A secondary battery cell typically 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 inserted and removed back and forth between the positive and negative electrodes.

[0127] In some embodiments, the secondary battery cell may further include an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0128] The liquid electrolyte includes an electrolyte salt and a solvent.

[0129] 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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0130] In certain embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may 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.

[0131] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, or 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, and additives that improve the low temperature performance of the battery cell.

[0132] In some embodiments, the secondary battery cell may include a housing, which may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0133] In some embodiments, the housing may be a sealed structure or a non-sealed structure.

[0134] For example, when the outer shell is a non-sealed structure, it protects the electrode assembly. A sealing bag may be located between the outer shell and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating member or an aluminum-plastic film. When the outer shell is a sealed structure, it encapsulates the electrode assembly, electrolyte, and other components.

[0135] In some embodiments, the housing includes an end cap and a shell, wherein the shell has an opening and the end cap covers the opening. The shell may have one or more openings. One or more end caps may also be provided.

[0136] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to the tab. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via a current collecting member. The electrode terminal may be provided on an end cap or on the housing.

[0137] The embodiments of the present application also provide an electronic device including the above-mentioned electrochemical device. The electronic device of the embodiment 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 can include, but is not limited to, a laptop computer, a pen-input computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD TV, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, a power-assisted bicycle, a bicycle, a lighting fixture, a toy, a game console, a clock, an electric tool, a flashlight, a camera, a large household battery and a lithium ion capacitor, etc.

[0138] Example

[0139] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further processing, and all instruments used in the examples are commercially available.

[0140] In each embodiment and comparative example of the present application, lithium-ion batteries were prepared and their performance was tested using the following method:

[0141] Example 1-1

[0142] 1. Preparation method of lithium-ion battery

[0143] (1) Preparation of positive electrode sheet

[0144] The positive electrode active material, lithium cobalt oxide (LiCoO2), conductive carbon black (conductive agent), and binder, polyvinylidene fluoride (PVDF), were dissolved in an N-methylpyrrolidone (NMP) solution at a weight ratio of 97.9:0.9:1.2 to form a positive electrode slurry. A 9μm aluminum foil was used as the positive electrode current collector. The positive electrode slurry was coated on the positive electrode current collector and dried, cold pressed, and cut to obtain a positive electrode sheet. The compacted density of the positive electrode active material layer of the positive electrode sheet was 4.2g / cm3 .

[0145] (2) Preparation of negative electrode sheet

[0146] The negative electrode active material artificial graphite, binder styrene-butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC) were dissolved in deionized water at a weight ratio of 97.4:1.4:1.2 to form a negative electrode slurry. A 10μm thick copper foil was used as the negative electrode current collector. The negative electrode slurry was coated on the negative electrode current collector, dried, cold pressed, and cut to obtain a negative electrode sheet. The compacted density of the negative electrode active material layer of the negative electrode sheet was 1.8g / cm 3 .

[0147] In the following embodiments and comparative examples, the negative electrode sheet has a main body protrusion and a corner protrusion.

[0148] (3) Preparation of isolation membrane

[0149] The diaphragm substrate is a 5μm thick polyethylene PE. A 2μm thick alumina ceramic layer is coated on one side of the diaphragm substrate. Finally, 2.5mg / 1540.25mm thick alumina is coated on both sides of the diaphragm substrate coated with a single ceramic layer. 2 The adhesive is polyvinylidene fluoride (PVDF), which is dried to form an adhesive layer. The porosity of the adhesive layer of the separator is 39%.

[0150] (4) Preparation of electrolyte

[0151] 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) are uniformly mixed in a mass ratio of 1:1:1:1:1, and then the electrolyte salt LiPF6 is dissolved in the above-mentioned non-aqueous solvent. After uniform mixing, an electrolyte is formed, wherein the mass percentage of LiPF6 based on the mass of the electrolyte is 12.5%.

[0152] (5) Assembly of lithium-ion batteries

[0153] The positive electrode sheet with the positive tab, the separator, and the negative electrode sheet with the negative tab are stacked in sequence, with the separator positioned between the positive and negative electrode sheets to provide insulation. The electrode assembly is then wound to form an electrode assembly. The electrode assembly is then placed in an aluminum-plastic film packaging, dehydrated at 80°C, and then injected with the aforementioned electrolyte and packaged. The lithium-ion battery is then produced through the following process steps: formation, degassing, and trimming. The following describes the testing methods for various parameters of various embodiments of this application.

[0154] 2. Performance test of lithium-ion batteries

[0155] (1) Cycle test and lithium deposition test

[0156] Normal temperature cycle test: In a 25°C environment, the electrode assembly is charged at a constant current of 3C to the full charge voltage (the battery is designed for a maximum voltage of 4.5V). Then, constant voltage charging is performed at the maximum voltage until the current reaches 0.02C. Then, constant current discharge is performed at a discharge current of 0.7C until the final voltage reaches 3.0V. The discharge capacity of the first cycle is recorded. The above conditions and steps are then repeated for 1000 charge and discharge cycles. The discharge capacity of the lithium-ion battery after 1000 charge and discharge cycles is recorded.

[0157] After testing at 25°C and 1000 charge and discharge cycles, when the battery is in a fully charged state (the battery is designed for a maximum voltage of 4.5V), it is disassembled to observe whether there is lithium deposition at the negative electrode interface / ear / protective glue. The criterion for judging whether there is lithium deposition is: the lithium deposition area is greater than 1 square millimeter and appears in ≥30% of the layers.

[0158] (3) Winding quality test

[0159] An electrode assembly is formed by placing a separator between two electrodes (a positive electrode and a negative electrode) of opposite polarity on an integrated winding machine. An X-ray device is used to measure the distance M (a value greater than 0.1 mm) between the edge of the negative electrode of the electrode assembly and the edge of the positive electrode in the width direction of the positive electrode. Samples are continuously prepared, and the total number of samples (T) (a total of 100) and the number of qualified products (N) are counted.

[0160] Winding ratio = N / T × 100%.

[0161] (4) Test method for average radial dimension R and height H

[0162] The pole piece is measured using a scanning electron microscope (SEM). The pole piece sample is placed in a scanning electron microscope, and the electron beam is scanned to obtain a high-resolution image of the raised structure. In the SEM image, image processing software can be used to draw a measurement line along the height direction of the raised structure. Based on the image pixel information and the known magnification, the height of the raised structure can be calculated. Similarly, the diameter of the raised structure is measured in the SEM image using image processing software. The average radial dimension is obtained by averaging the three values ​​at three locations. This can also be measured using a VR series shape and profile measurement microscope.

[0163] Examples 1-2 to 1-12, Comparative Examples 1-1 and 1-2

[0164] The differences between Examples 1-2 to 1-12, Comparative Example 1-1 and Comparative Example 1-2 and Example 1-1 are that the height H1 of the protrusion on the main body, the diameter R1 of the protrusion on the main body, H1 / 1000R1, the height H2 of the protrusion on the corner, the diameter R2 of the protrusion on the corner, H2 / 1000R2 and the values ​​of H1 / 1000R1-H2 / 1000R2 are different. See Table 1 for details.

[0165] Table 1

[0166]

[0167] According to Table 1, the retention rate of 1000 charge and discharge cycles at 25°C, the lithium deposition situation and the winding quality rate of each embodiment are improved compared with the comparative example. When the protrusion of the main body and the protrusion of the corner part in the electrode assembly meet the following conditions: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131, the lithium-ion battery has good cycle performance and the electrode assembly has a good winding quality rate.

[0168] According to Examples 1-3 to 1-6, when -0.015≤H1 / 1000R1-H2 / 1000R2≤0.0083, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0169] Example 2-1 to Example 2-9

[0170] The difference between Examples 2-1 to 2-9 and Example 1-1 is that the thickness D of the inorganic layer, the height H2 of the corner protrusion and H2 / D of Examples 2-1 to 2-9 are specially set, as shown in Table 2 for details.

[0171] Table 2

[0172]

[0173] According to Table 2, when the height H2 of the protrusion of the corner portion works synergistically with the thickness D of the inorganic layer, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0174] According to Examples 2-1 to 2-9, when 3.3≤H2 / D≤160, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0175] On this basis, according to Examples 2-3 to 2-5, it can be seen that when 6.7≤H2 / D≤60, the lithium-ion battery has better cycle performance and the electrode assembly has a better winding efficiency.

[0176] Example 3-1 to Example 3-10

[0177] The difference between Examples 3-1 to 3-10 and Example 1-1 is that the average particle size E of the inorganic particles in the inorganic layer of Examples 3-1 to 3-10, the height H2 of the protrusions at the corners, and H2 / E are specially set, as shown in Table 3 for details.

[0178] Table 3

[0179]

[0180] According to Table 3, when the height H2 of the protrusion of the corner portion works synergistically with the average particle size E of the inorganic particles in the inorganic layer, the lithium-ion battery has better cycle performance and the electrode assembly has a winding advantage.

[0181] According to Examples 3-1 to 3-10, when 10≤H2 / E≤800, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0182] On this basis, according to Examples 3-3 to 3-5, it can be seen that when 20≤H2 / E≤180, the ion battery has better cycle performance and the electrode assembly has a better winding efficiency.

[0183] Example 4-1 to Example 4-9

[0184] The difference between Examples 4-1 to 4-9 and Example 1-1 is 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. See Table 4 for details.

[0185] Table 4

[0186]

[0187] According to Table 4, when the height H2 of the protrusion of the corner portion works synergistically with the thickness F of the adhesive layer, the lithium-ion battery has better cycle performance and the electrode assembly has a winding advantage.

[0188] According to Example 1-1 and Example 4-1 to Example 4-9, when 4≤H2 / F≤800, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0189] On this basis, according to Examples 4-3 and 4-5, it can be seen that when 10≤H2 / F≤120, the ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0190] Example 5-1 to Example 5-9

[0191] The difference between Examples 5-1 to 5-9 and Example 1-1 is that the average particle size G of the bonding particles in the bonding layers of Examples 5-1 to 5-9, the height H2 of the protrusions at the corners, and H2 / G are different. See Table 5 for details.

[0192] Table 5

[0193]

[0194] According to Table 5, when the height H2 of the protrusions at the corners works synergistically with the average particle size G of the bonding particles in the adhesive layer, the lithium-ion battery has better cycle performance and the electrode assembly has a winding advantage.

[0195] According to Example 1-1 and Example 5-1 to Example 5-9, when 10≤H2 / G≤800, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0196] On this basis, according to Examples 5-3 to 5-5, it can be seen that when 20≤H2 / G≤600, the ion battery has better cycle performance and the electrode assembly has a better winding efficiency.

[0197] Example 6-1 to Example 6-9

[0198] The difference between Examples 6-1 to 6-9 and Example 1-1 is that the pore size P of the bonding layer, the height H2 of the corner protrusion, the diameter R2 of the corner protrusion, H2 / P and 1000R2 / P of Examples 6-1 to 6-9 are different. See Table 6 for details.

[0199] Table 6

[0200]

[0201] According to Table 6, when the height H2 and diameter R2 of the corner protrusion work together with the pore size P of the adhesive layer, the lithium-ion battery has better cycle performance and the electrode assembly has a winding advantage.

[0202] According to Example 1-1 and Example 6-1 to Example 6-9, when 0.2≤H2 / P≤160 and 3≤1000R2 / P≤20000, the lithium-ion battery has better cycle performance and the electrode assembly has better winding efficiency.

[0203] On this basis, according to Examples 6-2 to 6-4, it can be seen that when 0.4≤H2 / P≤120 and 20≤1000R2 / P≤6000, the ion battery has better cycle performance and the electrode assembly has a better winding efficiency.

[0204] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. An electrode assembly, characterized in that: include: At least two pole pieces and an isolation membrane, wherein the isolation membrane is provided between two adjacent pole pieces; At least one of the pole pieces includes a main body and corner portions located on both sides of the main body, the main body includes a plurality of main body protrusions, the corner portions include a plurality of corner protrusions, the height of the corner protrusions is H2 μm, and the orthographic projection of the corner protrusions along the thickness direction of the pole piece forms a second figure, and the average radial dimension of the second figure is R2 mm; The isolation film includes a base film and an inorganic layer, and the inorganic layer is coated on at least one side of the base film; the thickness of the inorganic layer is D μm, and the electrode assembly satisfies: 3.3≤H2 / D≤160.

2. The electrode assembly according to claim 1, wherein The height of the main body protrusion is H1μm, and the orthographic projection of the main body protrusion along the thickness direction of the pole piece constitutes a first figure. The average radial dimension of the first figure is R1mm, and the main body protrusion and the corner protrusion satisfy: -0.2665≤H1 / 1000R1-H2 / 1000R2≤0.0131.

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

267.

4. The electrode assembly according to claim 2, wherein: Satisfies: 0.015≤H1 / 1000R1≤0.025, and / or, satisfies: 0.0167≤H2 / 1000R2≤0.

025.

5. The electrode assembly according to claim 2, 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。 6. The electrode assembly according to claim 1, wherein: The electrode assembly satisfies: 6.7≤H2 / D≤60.

7. The electrode assembly according to claim 1, wherein: The thickness D of the inorganic layer and the height H2 of the protrusion at the corner portion have value ranges of 0.5≤D≤6 and 20≤H2≤80 respectively.

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

9. The electrode assembly according to claim 1, wherein: 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, characterized in that The electrode assembly satisfies: 20≤H2 / E≤180.

11. The electrode assembly according to claim 1, wherein The inorganic layer includes inorganic particles, the average particle size of the inorganic particles is E μm, and the average particle size E of the inorganic particles and the height H2 of the protrusion at the corner portion are in the range of 0.1≤E≤2, 20≤H2≤80 respectively.

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

13. The electrode assembly according to claim 1, wherein The isolation film further includes an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; The electrode assembly satisfies at least one of the following: (1) The thickness of the adhesive layer is F μm, 4≤H2 / F≤800; (2) The thickness of the adhesive layer is F μm, 10≤H2 / F≤120; (3) The thickness of the adhesive layer is F μm, and the thickness F of the adhesive layer and the height H2 of the protrusion at the corner portion are in the range of 0.1 ≤ F ≤ 5, 20 ≤ H2 ≤ 80 respectively; (4) 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 portion are: 0.5≤F≤2, 20≤H2≤60 respectively.

14. The electrode assembly according to any one of claims 1 to 12, characterized in that: The isolation film further includes an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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; (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.

15. The electrode assembly according to any one of claims 1 to 12, characterized in that: The isolation film further includes an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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 20≤H2 / G≤600; (2) The pore size of the adhesive layer is P μm, 0.4≤H2 / P≤120; (3) The pore size of the adhesive layer is P μm, 20≤1000R2 / P≤6000.

16. The electrode assembly according to any one of claims 1 to 12, characterized in that: The isolation film further includes an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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 the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner portion are in the range of 0.1≤G≤2, 20≤H2≤80 respectively; (2) The pore size of the adhesive layer is P μm, and the pore size P of the adhesive layer and the height H2 of the protrusion at the corner portion are in the range of 0.5 ≤ P ≤ 100, 20 ≤ H2 ≤ 80 respectively; (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 average radial dimension R2 of the second pattern are: 0.5≤P≤100, 0.3≤R2≤10 respectively.

17. The electrode assembly according to any one of claims 1 to 12, characterized in that: The isolation film further includes an adhesive layer, the adhesive layer is arranged on both sides of the base film, and the inorganic layer is arranged between the base film and the adhesive layer; 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 the average particle size G of the adhesive particles and the height H2 of the protrusion at the corner portion are in the range of 0.1 ≤ G ≤ 1, 20 ≤ H2 ≤ 60 respectively; (2) The pore size of the adhesive layer is P μm, and the pore size P of the adhesive layer and the height H2 of the protrusion at the corner portion are respectively in the range of: 0.5≤P≤50, 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 average radial dimension R2 of the second pattern are respectively: 0.5≤P≤50, 1≤R2≤3.

18. The electrode assembly according to any one of claims 1 to 12, characterized in that: The at least two pole pieces and the isolation film are wound around a winding core to form the electrode assembly. The main body protrusion is formed by the main body protruding toward the winding core, and the corner protrusion is formed by the corner protruding toward the winding core or by the corner protruding away from the winding core.

19. An electrochemical device, characterized in that include: A shell and at least one electrode assembly according to any one of claims 1 to 18, wherein the electrode assembly is arranged inside the shell.

20. An electronic device, characterized in that: The electronic device comprises the electrochemical device according to claim 19.

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