Electrochemical device and electronic equipment

Abstract

The application discloses an electrochemical device and an electronic device. The electrochemical device comprises an electrode assembly, the electrode assembly comprises a first electrode sheet, a diaphragm and a second electrode sheet which are arranged in a mutual laminated winding mode, and the polarity of the second electrode sheet is opposite to that of the first electrode sheet. The first electrode sheet has a plurality of flat areas and a plurality of corner areas which are arranged alternately along the winding direction of the first electrode sheet. The first electrode sheet comprises a current collector and an active material layer arranged on at least one side surface of the current collector. The active material layer on at least one side surface of the current collector is respectively provided with a punching area at at least part of the corner areas. The punching area is provided with a plurality of hexagonal micropores which are distributed at intervals. The aperture of the hexagonal micropore is D, and D satisfies 3 mu m <= D <= 50 mu m. The active material layer of the electrochemical device is provided with the punching area at the corner area of the electrode sheet. The punching area is provided with the hexagonal micropore. The arrangement density is high, the space utilization rate of the electrode sheet is improved, and compared with a dispersed transmission path formed by a circular micropore, the ion diffusion path is short, and the ion diffusion efficiency can be improved.

Description

Technical Field

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

[0002] Lithium-ion batteries, which contain lithium elements (including metallic lithium, lithium alloys, lithium ions, lithium polymers, etc.) in an electrochemical system, are widely used in consumer electronics and other fields due to their outstanding advantages such as high energy density, long cycle life and low self-discharge rate.

[0003] In the lithium battery manufacturing process, the cathode electrode, separator, and anode electrode are stacked and wound together to form a core, which is the core energy storage unit of the lithium battery. Among them, the cathode electrode, as the key carrier for lithium ions to insert / deintercalate during charging and discharging, plays a decisive role in battery performance due to its surface structure design.

[0004] Currently, in order to effectively improve the electrolyte wetting effect, the industry generally uses laser drilling technology to process circular micropore structures on the surface of the corner area of ​​the cathode electrode for ion transport. However, this method has low space utilization and the ion transport channels constructed by the circular micropores have long ion diffusion paths, resulting in low diffusion efficiency. Utility Model Content

[0005] The main objective of this application is to propose an electrochemical device that addresses the technical problems of low space utilization and long ion diffusion paths in existing lithium batteries, where circular micropores are used to construct ion transport channels in the corner regions of the cathode electrode.

[0006] To achieve the above objectives, this application proposes an electrochemical device comprising an electrode assembly, wherein the electrode assembly comprises a first electrode, a diaphragm, and a second electrode arranged in a stacked and wound manner, wherein the polarity of the second electrode is opposite to that of the first electrode.

[0007] The first electrode has a plurality of alternating straight regions and a plurality of corner regions along its winding direction. The first electrode includes a current collector and an active material layer disposed on at least one side surface of the current collector, and the active material layer on at least one side surface of the current collector has perforated areas at at least a portion of the corner regions.

[0008] The perforated area is provided with a plurality of spaced hexagonal micropores, the diameter of which is D, and D satisfies: 3μm≤D≤50μm.

[0009] Optionally, the plurality of hexagonal micropores are of the same size and have equal spacing.

[0010] Optionally, the active material layer on at least one side surface of the current collector is provided with a receiving groove, the receiving groove being used to expose a portion of the surface of the current collector, the receiving groove being located between any two adjacent perforated areas.

[0011] Optionally, along the winding direction of the first electrode, one end of the first electrode is the winding start end located in the inner circle of the electrode assembly, and the other end is the winding end located in the outer circle of the electrode assembly.

[0012] Along the direction from the receiving groove to the winding start end, the diameter and depth of the hexagonal micro-holes in the plurality of perforated areas between the receiving groove and the winding start end gradually decrease; and along the direction from the receiving groove to the winding end end, the diameter and depth of the hexagonal micro-holes in the plurality of perforated areas between the receiving groove and the winding end end gradually decrease.

[0013] Optionally, along the winding direction of the first electrode, one end of the first electrode is the winding start end located in the inner circle of the electrode assembly, and the other end is the winding end located in the outer circle of the electrode assembly.

[0014] Along the direction from the receiving groove to the winding start end, the spacing between the hexagonal micro-holes in the plurality of perforated areas between the receiving groove and the winding start end gradually increases; and along the direction from the receiving groove to the winding end end, the spacing between the hexagonal micro-holes in the plurality of perforated areas between the receiving groove and the winding end end gradually increases.

[0015] Optionally, the spacing between the plurality of hexagonal micropores is L, wherein L satisfies: 0.1mm ≤ L ≤ 2mm; and / or,

[0016] Along the winding direction of the first electrode, the width of the perforated area is W, and W satisfies: 5mm≤W≤20mm.

[0017] Optionally, the thickness of the active material layer is S, and the pore depth of the hexagonal micropores is H, wherein H satisfies: 0.3S≤H≤0.7S, and / or, S satisfies: 20μm≤S≤200μm.

[0018] Optionally, along the winding direction of the first electrode, one end of the first electrode is the winding start end located in the inner circle of the electrode assembly, and the other end is the winding end located in the outer circle of the electrode assembly.

[0019] The receiving groove is provided with the punching area at the K1 consecutive corner areas on the side facing the winding start end, and the receiving groove is provided with the punching area at the K2 consecutive corner areas on the other side facing the winding end end.

[0020] The first electrode has N layers; when N is an even number, N, K1, and K2 satisfy: 1≤K1≤0.5*N-1, 1≤K2≤0.5*N-1; when N is an odd number, N, K1, and K2 satisfy: 1≤K1≤0.5*(N-1), 1≤K2≤0.5*(N-1).

[0021] Optionally, in the width direction of the first electrode, there is a first spacing E1 between one edge of the active material layer and the nearest hexagonal micropore, and a second spacing E2 between the other edge of the active material layer and the nearest hexagonal micropore, wherein E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

[0022] This invention also proposes an electronic device comprising the electrochemical apparatus described above.

[0023] In the electrochemical device of this application, the first electrode has multiple alternating straight regions and multiple corner regions along its winding direction. The active material layer on at least one side of the current collector has perforated regions at at least part of the corner regions. The perforated regions have multiple spaced hexagonal micropores with a pore diameter D of 3μm to 50μm. The hexagon is a regular polygon that can achieve seamless close packing in a unit area in a plane. The distance from its vertex to the center is equal and the minimum spacing between adjacent micropores is uniform. This makes the arrangement density of hexagonal micropores greater than that of circular micropores within the same perforated region area, thereby increasing the number of ion transport channels per unit area and improving the space utilization of the electrode. Furthermore, since the distance from each side of the hexagon to the center is smaller than the radius of the circle, and the transport channels formed between adjacent micropores are distributed in a regular hexagonal grid, ions can pass through the micropore array along a shorter straight distance when passing through the perforated region. Compared with the dispersed transport path formed by circular micropores, the ion diffusion path is shorter, which can improve the ion diffusion efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the electrode assembly of an electrochemical device in one embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of the first electrode in one embodiment of this application from a certain perspective;

[0026] Figure 3 This is a schematic diagram of the structure of the first electrode in one embodiment of this application from another perspective;

[0027] Figure 4 This is a schematic diagram of the structure of the first electrode in another embodiment of this application;

[0028] Figure 5 This is a schematic diagram of a portion of the first electrode in another embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a portion of the first electrode sheet in another embodiment of this application;

[0030] Figure 7 This is a schematic diagram of the structure of the first electrode in another embodiment of this application;

[0031] Explanation of icon numbers:

[0032]

[0033]

[0034] The realization of the purpose, functional features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] The solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments in this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0037] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0038] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0039] This application provides an electrochemical device, referring to... Figures 1 to 3 The electrochemical device includes an electrode assembly, which includes a first electrode 100, a diaphragm 200, and a second electrode 300 that are stacked and wound around each other, with the second electrode 300 having the opposite polarity to the first electrode 100.

[0040] The first electrode 100 has a plurality of alternating straight regions 100P and a plurality of corner regions 100G along its winding direction. The first electrode 100 includes a current collector 110 and an active material layer 120 disposed on at least one side surface of the current collector 110. The active material layer 120 on at least one side surface of the current collector 110 has a perforated region 121 at at least part of the corner region 100G.

[0041] The perforated area 121 is provided with a plurality of hexagonal micropores 122 spaced apart. The diameter of the hexagonal micropores 122 is D, and D satisfies: 3μm≤D≤50μm.

[0042] The electrochemical devices involved in this application include any device in which an electrochemical reaction occurs to convert chemical energy into electrical energy and vice versa. Specific, non-limiting embodiments include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries, etc.

[0043] like Figure 1 As shown, the electrode assembly, as the basic structure of the electrochemical device, consists of a first electrode 100, a separator 200, and a second electrode 300. These three components are stacked and wound together in the order of "first electrode 100 - separator 200 - second electrode 300" to form a core structure. The second electrode 300 has the opposite polarity to the first electrode 100. Specifically, the first electrode 100 can be a cathode electrode (also called a positive electrode), and the second electrode 300 is an anode electrode (also called a negative electrode). The anode electrode serves as the source of lithium ions during battery discharge, undergoing a lithium ion release reaction. The cathode electrode serves as the source of lithium ions during battery charging, undergoing a lithium ion release reaction. The separator 200, located between the anode and cathode electrodes, plays a crucial role in isolating the electrodes and preventing direct contact and short circuits, while simultaneously allowing lithium ions to pass through, ensuring the smooth progress of the electrochemical reaction.

[0044] The first electrode 100 has multiple alternating straight regions 100P and multiple corner regions 100G along its winding direction (i.e., the circumferential direction of the electrode assembly). During the winding process, the section of the electrode parallel to the axis of the electrode assembly is the straight region 100P, and the section of the electrode bending with the curvature of the electrode assembly is the corner region 100G. The straight regions 100P and corner regions 100G are periodically alternating along the winding direction (e.g., two corner regions 100G are formed for each turn of winding).

[0045] like Figure 2 and Figure 3 As shown, the first electrode 100 includes a current collector 110 and an active material layer 120. The current collector 110 is a conductive substrate, preferably aluminum foil, and its surface can be electrochemically etched or sandblasted to improve its adhesion to the active material layer 120. The active material layer 120 is coated on at least one side of the current collector 110, preferably both sides, to improve energy density. Its composition includes active material, conductive agent (such as carbon black, graphene), and binder (such as polyvinylidene fluoride PVDF).

[0046] The active material layer 120 on at least one side surface of the current collector 110 has a perforated area 121 at at least part of the corner area 100G. Specifically, it may be provided only in the corner area 100G where stress is easily accumulated, or in all corner areas 100G, depending on the battery capacity and cycle requirements.

[0047] The perforated area 121 is fabricated with multiple spaced hexagonal micropores 122. These hexagonal micropores 122 can be arranged in an array, for example, the perforated area 121 has m rows and n columns of hexagonal micropores 122. The shape of the hexagonal micropores 122 can be regular hexagons. The regular hexagonal micropores 122 have the characteristic of "seamless close-packed". The edges of adjacent regular hexagonal micropores 122 can fit together without any gaps. Moreover, the distance from each vertex of the regular hexagon to the center is equal, and the distance from each side to the center (radius of the inscribed circle) is uniform, which can ensure that the minimum spacing between adjacent micropores is consistent and avoid local ion transport congestion.

[0048] The pore diameter D (defined as the diameter of the circumcircle of the hexagonal micropore 122) is 3μm to 50μm. For example, the pore diameter D of the hexagonal micropore 122 can be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, ..., 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, ..., 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm or 50μm, or within the range of any two of the above values.

[0049] In the electrochemical device of this application, the first electrode 100 has a plurality of alternating straight regions 100P and a plurality of corner regions 100G along its winding direction. The active material layer 120 on at least one side of the current collector 110 has perforated regions 121 at at least a portion of the corner regions 100G. The perforated regions 121 have a plurality of distributed hexagonal micropores. The pore size D of the hexagonal micropores is 3μm to 50μm. The hexagon is a regular polygon that can achieve seamless close packing per unit area in a plane, and the distance from its vertex to the center is equal and the minimum spacing between adjacent micropores is uniform. This results in a higher density of hexagonal micropores 122 within the same perforated area 121 compared to circular micropores, thereby increasing the number of ion transport channels per unit area and improving the space utilization of the electrode. Furthermore, since the distance from each side of the hexagon to the center is smaller than the radius of the circle, and the transport channels formed between adjacent micropores are distributed in a regular hexagonal grid pattern, ions can pass through the micropore array along a shorter straight-line distance when passing through the perforated area 121. Compared to the dispersed transport path formed by circular micropores, the ion diffusion path is shorter, which can improve the ion diffusion efficiency.

[0050] In some embodiments, refer to Figure 2 and Figure 3 Multiple hexagonal micropores 122 are identical in size and have equal spacing. In this embodiment, the identical size and equal spacing of the hexagonal micropores 122 are specifically manifested in the fact that the diameter and depth of the hexagonal micropores 122 are the same, and the spacing between the hexagonal micropores 122 is also equal, to ensure the uniformity of the ion transport channels within the perforated area 121. Furthermore, based on this, it can be that the hexagonal micropores 122 are identical in size and have equal spacing between them in different perforated areas 121.

[0051] In some embodiments, refer to Figures 2 to 4 The active material layer 120 on at least one side surface of the current collector 110 is provided with a receiving groove 120C. The receiving groove 120C is used to expose part of the surface of the current collector 110. The receiving groove 120C is located between any two adjacent perforated areas 121.

[0052] In this embodiment, the active material layer 120 on one or both surfaces of the current collector 110 is provided with a receiving groove 120C. The receiving groove 120C, also known as the tab mounting groove, penetrates the active material layer 120 along its thickness direction, exposing part of the surface of the current collector 110. The size of the receiving groove 120C is adapted to the tab, and the tab can be accommodated in the receiving groove 120C and connected to the current collector 110 to realize the current conduction / conduction. The connection method can be welding (such as laser welding, ultrasonic welding), etc., including but not limited to these. The receiving groove 120C is located between any two adjacent perforated areas 121. That is, the receiving groove 120C is located at a flat area 100P, and the corner areas 100G on both sides of the flat area 100P are respectively provided with perforated areas 121, so that the receiving groove 120C is located between the two adjacent perforated areas 121.

[0053] During the charging and discharging process of the electrochemical device, the current is introduced into / outlet from the current collector 110 through the tab. Because the current collector 110 has a certain resistance, a voltage drop will occur when the current is transmitted from the tab to both ends of the electrode (i.e., the starting end and the ending end of the winding). This results in the current density on the electrode surface exhibiting a distribution characteristic of "high in the tab area and low in the edge area". At the same time, lithium ions need to migrate in the active material layer 120 to complete the insertion / extraction reaction. The concentration gradient is consistent with the current density distribution, that is, the ion consumption / generation rate is high near the tab and the concentration requirement is high, while the opposite is true in the areas at both ends of the electrode.

[0054] The containment tank 120C is located between two adjacent perforated areas 121. When lithium ions migrate from the tab to the perforated areas 121 on both sides, they can be rapidly transported and diffused through the multi-dimensional ion transport network constructed in the perforated areas 121. Furthermore, the hexagonal micropores 122 in the perforated areas 121 can provide electrolyte storage space, accelerate the electrolyte wetting speed, increase the CB value at the corner area 100G, and improve corner lithium deposition.

[0055] In some embodiments, refer to Figures 4 to 6 Along the winding direction of the first electrode 100, one end of the first electrode 100 is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly.

[0056] Along the direction from the receiving groove 120C to the winding start end, the diameter and depth of the hexagonal micro-holes 122 in the perforated areas 121 between the receiving groove 120C and the winding start end gradually decrease; and along the direction from the receiving groove 120C to the winding end end, the diameter and depth of the hexagonal micro-holes 122 in the perforated areas 121 between the receiving groove 120C and the winding end end gradually decrease.

[0057] In this embodiment, considering the voltage drop and ion concentration difference generated during current transmission in the current collector 110, the design of the hexagonal micropores 122 in the perforated area 121 at at least some corner regions 100G is gradient optimized. Along the winding direction of the first electrode 100, by adjusting the aperture and depth of the hexagonal micropores 122 in the perforated area 121 at different corner regions 100G, the volume of the ion transmission channel is matched with the space requirements for ion transmission and electrolyte storage.

[0058] Along the winding direction of the first electrode 100, one end is the winding start end located in the inner ring of the electrode assembly after winding, and the other end is the winding end located in the outer ring of the electrode assembly; the receiving groove 120C is located between the winding start end and the winding end end, and ≥2 perforated areas 121 are distributed on both sides (e.g., 8 perforated areas 121 are provided on the inner ring side and 8 perforated areas 121 are provided on the outer ring side, for a total of 16 perforated areas 121 symmetrically distributed relative to the receiving groove 120C). Taking the receiving groove 120C as a reference, along the two directions of receiving groove 120C → winding start end and receiving groove 120C → winding end end, the diameter and depth of the hexagonal micro-holes 122 in several perforated areas 121 on the path gradually decrease; that is, the perforated area 121 closer to the receiving groove 120C (electrode tab) has the largest diameter and the deepest depth of the hexagonal micro-holes 122; the further away from the receiving groove 120C (i.e., the closer to the winding start end / winding end end of the electrode), the smaller the diameter and the shallower the depth of the hexagonal micro-holes 122.

[0059] The hexagonal micropores 122 in the perforated areas 121 closest to the accommodating tank 120C have the largest diameter and deepest pores, resulting in the largest channel volume. Their ion transport channel volume ratio is high, which can quickly conduct ions generated near the tab due to high current density and store more electrolyte. The hexagonal micropores 122 in the edge perforated areas 121 near the winding start / end have the smallest diameter and shallowest pore depth, resulting in the smallest channel volume and a lower channel volume ratio. This satisfies the low ion transport and electrolyte storage requirements in the edge area while retaining more active material and avoiding capacity loss due to excessive channel design.

[0060] The aforementioned gradient design of the ion transport channel volume precisely matches the gradient distribution of "current density - ion transport and electrolyte storage requirements", which helps to solve the problems of ion congestion in the tab area, insufficient electrolyte storage space, and waste of channels in the edge area. It achieves a precise match between the ion transport channel volume and the requirements of ion transport and electrolyte storage, significantly reduces concentration polarization, and improves lithium plating at corners.

[0061] In some embodiments, refer to Figure 7 Along the winding direction of the first electrode 100, one end of the first electrode 100 is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly.

[0062] Along the direction from the receiving groove 120C to the winding start end, the spacing between the hexagonal micro-holes 122 in the perforated areas 121 between the receiving groove 120C and the winding start end gradually increases; and along the direction from the receiving groove 120C to the winding end end, the spacing between the hexagonal micro-holes 122 in the perforated areas 121 between the receiving groove 120C and the winding end end gradually increases.

[0063] In this embodiment, considering the voltage drop and ion concentration gradient difference generated during current transmission in the current collector 110, gradient optimization is performed on the design of the hexagonal micro-holes 122 in at least some corner regions 100G of the perforated area 121. Along the winding direction of the first electrode 100, by adjusting the hole spacing L of the hexagonal micro-holes 122 in the perforated area 121 at different corner regions 100G, the ion transport channel density is matched with the requirements of ion transport and electrolyte storage. The hole spacing involved refers to the distance between the edges of two adjacent hexagonal micro-holes 122 along the length or width direction of the first electrode 100, or other directions. Optionally, for any perforated area 121, the spacing between any two adjacent hexagonal micro-holes 122 within the area is equal. This equality can be completely equal or approximately equal, allowing for slight errors.

[0064] Along the winding direction of the first electrode 100, one end is the winding start end located in the inner ring of the electrode assembly after winding (the point furthest from the receiving groove 120C in the arc length direction is the inner ring end point), and the other end is the winding end located in the outer ring of the electrode assembly (the point furthest from the receiving groove 120C in the arc length direction is the outer ring end point); the receiving groove 120C is located between the winding start end and the winding end end, and ≥2 perforated areas 121 are distributed on both sides (e.g., 8 perforated areas 121 are provided on the inner ring side and 8 perforated areas 121 are provided on the outer ring side, for a total of 16 perforated areas 121 symmetrically distributed relative to the receiving groove 120C). Taking the receiving groove 120C as a reference, along the two directions of receiving groove 120C → winding start end and receiving groove 120C → winding end end, the spacing between the hexagonal micro-holes 122 in the several perforated areas 121 on the path gradually increases; that is, the spacing between the hexagonal micro-holes 122 is the smallest in the perforated area 121 close to the receiving groove 120C (tab); the further away from the receiving groove 120C (i.e. closer to the winding start end / winding end end of the electrode) the perforated area 121 is, the larger the spacing between the hexagonal micro-holes 122 is.

[0065] The hexagonal micropores 122 on both sides of the receiving tank 120C, which are closest to the perforated area 121, have the smallest hole spacing and the highest channel density. Their ion transport channel area accounts for a high proportion, which can quickly conduct ions generated near the tab due to high current density and store more electrolyte. The hexagonal micropores 122 on the edge perforated area 121 near the starting / ending end of winding have the largest hole spacing, the lowest channel density, and a lower channel area proportion. This satisfies the low ion transport and electrolyte storage requirements of the edge area while retaining more active material and avoiding capacity loss due to excessive channel design.

[0066] The aforementioned gradient design of ion transport channel density precisely matches the gradient distribution of "current density - ion transport and electrolyte storage requirements", which helps to solve the problems of ion congestion in the tab area, limited electrolyte storage space, and waste of channels in the edge area. It achieves a precise match between ion transport channel density and ion transport and electrolyte storage requirements, significantly reduces concentration polarization, and improves lithium plating at corners.

[0067] In some embodiments, the spacing between the plurality of hexagonal micropores 122 is L, where L satisfies: 0.1mm ≤ L ≤ 2mm; and / or,

[0068] Along the winding direction of the first electrode 100, the width of the perforated area 121 is W, and W satisfies: 5mm≤W≤20mm.

[0069] For example, the spacing L between the multiple hexagonal micro-holes 122 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 1mm, or fall within the range of any two of the above values. By setting the spacing L between the hexagonal micro-holes 122 to between 0.1mm and 2mm, the spacing L is made appropriate, neither too small nor too large, thus meeting the actual manufacturing requirements.

[0070] For example, such as Figure 2 As shown, along the winding direction of the first electrode 100 (i.e., the length direction of the first electrode 100), the width W of the perforated area 121 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, or 20mm, or fall within the range of any two of the above values. By setting the width W of the perforated area 121 to between 5mm and 20mm, the width of the perforated area 121 is adapted to the arc length of the corner area 100G, avoiding it being too narrow or too wide.

[0071] In some embodiments, the thickness of the active material layer 120 is S, and the pore depth of the hexagonal micropores 122 is H, where H satisfies: 0.3S≤H≤0.7S, and / or, S satisfies: 20μm≤S≤200μm.

[0072] The thickness S of the active material layer 120 refers to the thickness of the active material layer 120 coated on one side of the current collector 110. For example, the pore depth H of the hexagonal micropores 122 can be 0.3S, 0.4S, 0.5S, 0.6S, or 0.7S, or fall within any two of these values. By limiting the pore depth H of the hexagonal micropores 122 to a range of 0.3S to 0.7S, the pore depth is kept appropriate, avoiding both insufficient liquid storage space due to excessively shallow pores and decreased structural strength of the active material layer 120 due to excessively deep pores. For example, the thickness S of the active material layer 120 can be 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, or within the range of any two of the above values.

[0073] In some embodiments, refer to Figures 2 to 4 Along the winding direction of the first electrode 100, one end of the first electrode 100 is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly.

[0074] A perforated area 121 is provided at the K1 corner areas 100G arranged continuously on the side of the receiving groove 120C facing the winding start end, and a perforated area 121 is provided at the K2 corner areas 100G arranged continuously on the other side of the receiving groove 120C facing the winding end.

[0075] The first electrode 100 has N layers; when N is even, N, K1, and K2 satisfy: 1≤K1≤0.5*N-1, 1≤K2≤0.5*N-1; when N is odd, N, K1, and K2 satisfy: 1≤K1≤0.5*(N-1), 1≤K2≤0.5*(N-1).

[0076] In this embodiment, the range of the number (K1, K2) of the perforated areas 121 on both sides of the receiving groove 120C is related to the number of layers N formed by the winding of the first electrode 100. Specifically, the number of layers N of the first electrode 100 can refer to the number of complete layers in the thickness direction formed by the first electrode 100 after winding (two layers in one winding), excluding the quarter turn at the winding end (such as incomplete layers where the outer ring only covers 1 / 2 of the width of the electrode assembly after winding are not included in N).

[0077] Along the winding direction of the first electrode 100, the corner regions 100G on both sides of the receiving groove 120C are continuously distributed in a ring. That is, on the side of the receiving groove 120C facing the winding start end (inner ring), the corner regions 100G are arranged continuously in sequence along the direction of receiving groove 120C → inner ring (denoted as the first inner corner region 100G, the second inner corner region 100G, ..., the K1 inner corner region 100G); on the side of the receiving groove 120C facing the winding end end (outer ring), the corner regions 100G are arranged continuously in sequence along the direction of receiving groove 120C → outer ring (denoted as the first outer corner region 100G, the second outer corner region 100G, ..., the K2 outer corner region 100G), and there are no discrete or intermittently distributed corner regions 100G. K1 is the number of corner areas 100G of the continuously perforated areas 121 on the side of the receiving groove 120C facing the winding start end; K2 is the number of corner areas 100G100G of the continuously perforated areas 121 on the side of the receiving groove 120C facing the winding end end; K1 and K2 are both positive integers (≥1, to ensure that there is at least one perforated area 121 on both sides of the receiving groove 120C to achieve ion transport).

[0078] Specifically, there are two scenarios: when N is even or odd.

[0079] Scenario 1: When N is an even number (e.g., N = 12, 14, 16, 18, 20), 1 ≤ K1 ≤ 0.5 * N - 1, and 1 ≤ K2 ≤ 0.5 * N - 1. Taking N = 20 as an example, 1 ≤ K1 ≤ 9 and 1 ≤ K2 ≤ 9. That is, when the first electrode 100 has 20 layers, the receiving groove 120C facing the winding start end has K1 consecutive corner areas 100G with perforated areas 121 respectively. K1 can be 1, 2, 3, 4, 5, 6, 7, 8, or 9. The receiving groove 120C facing the winding end end has K2 consecutive corner areas 100G with perforated areas 121 respectively. K2 can be 1, 2, 3, 4, 5, 6, 7, 8, or 9, depending on the actual needs.

[0080] Scenario 2: When N is an odd number (e.g., N = 13, 15, 17, 19, 21), 1 ≤ K1 ≤ 0.5 * (N-1), 1 ≤ K2 ≤ 0.5 * (N-1). Taking N = 21 as an example, 1 ≤ K1 ≤ 10, 1 ≤ K2 ≤ 10. That is, when the first electrode 100 has 21 layers, the receiving groove 120C facing the winding start end has K1 consecutive corner areas 100G with perforated areas 121 respectively. K1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. The receiving groove 120C facing the winding end end has K2 consecutive corner areas 100G with perforated areas 121 respectively. K2 can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, depending on the actual needs.

[0081] In some embodiments, refer to Figure 2 In the width direction of the first electrode 100, there is a first distance E1 between one edge of the active material layer 120 and the hexagonal micropore 122 that is closest to it, and there is a second distance E2 between the other edge of the active material layer 120 and the hexagonal micropore 122 that is closest to it. E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

[0082] Along the width direction of the first electrode 100 (perpendicular to the distribution direction of the perforated area 121), the active material layer 120 has two side edges. The edge closer to the width direction of the electrode is defined as the first side edge of the active material layer 120, and the other side edge is defined as the second side edge of the active material layer 120.

[0083] E1 is the straight-line distance between the first side edge of the active material layer 120 and the hexagonal micropore 122 on the corresponding side edge of the perforated area 121 (one side of the perforated area 121 along the width direction of the electrode); E2 is the straight-line distance between the second side edge of the active material layer 120 and the hexagonal micropore 122 on the corresponding side edge of the perforated area 121 (the other side of the perforated area 121 along the width direction of the electrode).

[0084] Optionally, E1 and E2 must satisfy 0≤E1≤3mm and 0≤E2≤3mm. For example, E1 and E2 can be 1mm, 2mm or 3mm, or fall within the range of any two of the above values.

[0085] This application also proposes an electronic device that includes the electrochemical device described in the foregoing embodiments. The specific structure of the electrochemical device is the same as described in the foregoing embodiments. Since this electronic device adopts all the technical solutions of all the foregoing embodiments, it has at least all the technical effects brought about by the technical solutions of the foregoing embodiments, and will not be described in detail here.

[0086] The electronic device described in this application is not particularly limited and can be any electronic device known in the prior art. The electrochemical device described in this application is also not particularly limited in its use and can be used in any electronic device known in the prior art. According to some embodiments of this application, the electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, and robotic dogs.

[0087] The above description is only a part or preferred embodiment of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. An electrochemical device, characterized in that, The device includes an electrode assembly comprising a first electrode (100), a diaphragm (200), and a second electrode (300) arranged in a stacked and wound manner, wherein the second electrode (300) has the opposite polarity to the first electrode (100). The first electrode (100) has a plurality of alternating straight regions (100P) and a plurality of corner regions (100G) along its winding direction. The first electrode (100) includes a current collector (110) and an active material layer (120) disposed on at least one side surface of the current collector (110). The active material layer (120) on at least one side surface of the current collector (110) has perforated areas (121) at at least a portion of the corner regions (100G). The perforated area (121) is provided with a plurality of spaced hexagonal micropores (122), the diameter of the hexagonal micropores (122) is D, and D satisfies: 3μm≤D≤50μm.

2. The electrochemical device according to claim 1, characterized in that, The multiple hexagonal micropores (122) are the same size and have equal spacing.

3. The electrochemical device according to claim 1, characterized in that, The active material layer (120) on at least one side surface of the current collector (110) is provided with a receiving groove (120C), the receiving groove (120C) is used to expose part of the surface of the current collector (110), and the receiving groove (120C) is located between any two adjacent perforated areas (121).

4. The electrochemical device according to claim 3, characterized in that, Along the winding direction of the first electrode (100), one end of the first electrode (100) is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly. Along the direction from the receiving groove (120C) to the winding start end, the diameter and depth of the hexagonal micro-holes (122) in the plurality of perforated areas (121) between the receiving groove (120C) and the winding start end gradually decrease; and along the direction from the receiving groove (120C) to the winding end end, the diameter and depth of the hexagonal micro-holes (122) in the plurality of perforated areas (121) between the receiving groove (120C) and the winding end end gradually decrease.

5. The electrochemical device according to claim 3, characterized in that, Along the winding direction of the first electrode (100), one end of the first electrode (100) is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly. Along the direction from the receiving groove (120C) to the winding start end, the spacing between the hexagonal micro-holes (122) in the plurality of perforated areas (121) between the receiving groove (120C) and the winding start end gradually increases; and along the direction from the receiving groove (120C) to the winding end end, the spacing between the hexagonal micro-holes (122) in the plurality of perforated areas (121) between the receiving groove (120C) and the winding end end gradually increases.

6. The electrochemical device according to any one of claims 1 to 5, characterized in that, The spacing between the plurality of hexagonal micropores (122) is L, wherein L satisfies: 0.1mm ≤ L ≤ 2mm; and / or, Along the winding direction of the first electrode (100), the width of the perforated area (121) is W, and W satisfies: 5mm≤W≤20mm.

7. The electrochemical device according to any one of claims 1 to 5, characterized in that, The thickness of the active material layer (120) is S, and the pore depth of the hexagonal micropore (122) is H, wherein H satisfies: 0.3S≤H≤0.7S, and / or, wherein S satisfies: 20μm≤S≤200μm.

8. The electrochemical device according to claim 3, characterized in that, Along the winding direction of the first electrode (100), one end of the first electrode (100) is the winding start end located in the inner ring of the electrode assembly, and the other end is the winding end located in the outer ring of the electrode assembly. The receiving groove (120C) is provided with the punching area (121) at the K1 consecutively arranged corner areas (100G) on the side facing the winding start end, and the receiving groove (120C) is provided with the punching area (121) at the K2 consecutively arranged corner areas (100G) on the other side facing the winding end end. The first electrode (100) has N layers; when N is an even number, N, K1, and K2 satisfy: 1≤K1≤0.5*N-1, 1≤K2≤0.5*N-1; when N is an odd number, N, K1, and K2 satisfy: 1≤K1≤0.5*(N-1), 1≤K2≤0.5*(N-1).

9. The electrochemical device according to any one of claims 1 to 5, characterized in that, In the width direction of the first electrode (100), there is a first spacing E1 between one side edge of the active material layer (120) and the hexagonal micropore (122) closest to it, and there is a second spacing E2 between the other side edge of the active material layer (120) and the hexagonal micropore (122) closest to it. E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

10. An electronic device, characterized in that, Includes the electrochemical device as described in any one of claims 1 to 9.

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