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 comprises a current collector and an active material layer arranged on the current collector. The active material layer is provided with a perforated area along the length direction of the first electrode sheet. The perforated area is provided with a plurality of polygonal micropores which are arranged at intervals. The aperture of the polygonal micropores is D, and D satisfies 3 microns <= D <= 50 microns. The electrochemical device is provided with the perforated area in the active material layer of the electrode sheet. The perforated area is provided with a plurality of polygonal micropores which are arranged at intervals. The aperture of the polygonal micropores is D, and D satisfies 3 microns <= D <= 50 microns. Compared with the circular micropores, the polygonal micropores have a large arrangement density, and the space utilization rate of the electrode sheet can be improved. Compared with the dispersed transmission path formed by the circular micropores, 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, as electrochemical systems containing lithium (including metallic lithium, lithium alloys, lithium-ion, and lithium polymer batteries), 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. Against the backdrop of global energy transition and green development, further improving the energy density, charge / discharge efficiency, and cycle stability of lithium-ion batteries has become a core driving force for technological iteration in the industry.

[0003] In lithium battery manufacturing, the anode electrode, as a key carrier for lithium ion insertion / extraction, plays a decisive role in battery performance due to its surface structure design.

[0004] Currently, in order to reduce lithium-ion diffusion resistance and improve battery reaction kinetics, the industry generally uses laser drilling technology to process circular micropore structures on the surface of the anode 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-ion batteries, which use circular micropores to construct ion transport channels on the electrodes.

[0006] To achieve the above objectives, this application provides 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, the second electrode having the opposite polarity to the first electrode;

[0007] The first electrode includes a current collector and an active material layer disposed on the current collector. The active material layer has a perforated area along the length direction of the first electrode. The perforated area has a plurality of spaced polygonal micropores. The diameter of the polygonal micropores is D, and D satisfies: 3μm≤D≤50μm.

[0008] In some embodiments, there are multiple perforated areas, and the multiple perforated areas are sequentially distributed along the length direction of the first electrode sheet;

[0009] The active material layer is provided with a recess for exposing a partial surface of the current collector to connect the tab, the plurality of perforated regions includes a third perforated region, the third perforated region covers the recess, and the pore diameter of the polygonal micropores in the third perforated region is not equal to the pore diameter of the polygonal micropores in at least a part of the remaining perforated regions.

[0010] In some embodiments, the plurality of perforated regions further includes a first perforated region and a second perforated region, and the first perforated region, the second perforated region and the third perforated region are sequentially distributed along the length direction of the first pole piece;

[0011] The pore diameter of the polygonal micropores in the first perforated region is D1 and the pore spacing is L1, the pore diameter of the polygonal micropores in the second perforated region is D2 and the pore spacing is L2, the pore diameter of the polygonal micropores in the third perforated region is D3 and the pore spacing is L3, D1, D2 and D3 satisfy: D1<D2<D3, and L1, L2 and L3 satisfy: L1=L2=L3.

[0012] In some embodiments, the perforated regions further include a fourth perforated region and a fifth perforated region, and the first perforated region, the second perforated region, the third perforated region, the fourth perforated region and the fifth perforated region are sequentially distributed along the length direction of the first pole piece;

[0013] The pore diameter of the polygonal micropores in the fourth perforated region is D4 and the pore spacing is L4, the pore diameter of the polygonal micropores in the fifth perforated region is D5 and the pore spacing is L5, D3, D4 and D5 satisfy: D3≥D4≥D5, and L3, L4 and L5 satisfy: L3=L4=L5.

[0014] In some embodiments, D3, D4 and D5 satisfy: D3=D4=D5.

[0015] In some embodiments, the plurality of perforated regions further includes a first perforated region and a second perforated region, and the first perforated region, the second perforated region and the third perforated region are sequentially distributed along the length direction of the first pole piece;

[0016] The pore diameter of the polygonal micropores in the first perforated region is D1 and the pore spacing is L1, the pore diameter of the polygonal micropores in the second perforated region is D2 and the pore spacing is L2, the pore diameter of the polygonal micropores in the third perforated region is D3 and the pore spacing is L3, D1, D2 and D3 satisfy: D1>D2>D3, and L1, L2 and L3 satisfy: L1>L2>L3.

[0017] In some embodiments, the plurality of perforated regions further includes a fourth perforated region and a fifth perforated region, and the first perforated region, the second perforated region, the third perforated region, the fourth perforated region and the fifth perforated region are sequentially distributed along the length direction of the first pole piece;

[0018] The pore diameter of the polygonal micropores in the fourth perforated region is D4, and the pore spacing is L4; the pore diameter of the polygonal micropores in the fifth perforated region is D5, and the pore spacing is L5. The D3, D4 and D5 satisfy: D3≤D4≤D5, and the L3, L4 and L5 satisfy: L3<L4<L5.

[0019] In some embodiments, the D3, D4 and D5 satisfy: D3=D4=D5.

[0020] In some embodiments, the hole depth of the polygonal micropores in the first perforated region is H1, the hole depth of the polygonal micropores in the second perforated region is H2, the hole depth of the polygonal micropores in the third perforated region is H3, the hole depth of the polygonal micropores in the fourth perforated region is H4, and the hole depth of the polygonal micropores in the fifth perforated region is H5. The H1, H2, H3, H4 and H5 satisfy: H1<H2<H3, and H3≥H4≥H5.

[0021] In some embodiments, the H3, H4 and H5 satisfy: H3=H4=H5.

[0022] In some embodiments, along the length direction of the first pole piece, the spacing between the second perforated region and the edge of the groove is C1, and the C1 satisfies: C1≥6mm; and / or,

[0023] Along the length direction of the first pole piece, the spacing between the fourth perforated region and the edge of the groove is C2, and the C2 satisfies: C2≥6mm.

[0024] In some embodiments, one end of the first pole piece is a winding start end located at the inner ring of the electrode assembly after winding, and the other end is a winding end termination located at the outer ring of the electrode assembly after winding;

[0025] The fifth perforated region, the fourth perforated region, the third perforated region, the second perforated region and the first perforated region are sequentially distributed from the winding start end toward the winding termination end.

[0026] In some embodiments, the size and the pore spacing of the plurality of polygonal micropores are respectively equal.

[0027] In some embodiments, the pore spacing of the plurality of polygonal micropores is L, and the L satisfies: 2D≤L≤3D; and / or,

[0028] The ratio of the depth of the polygonal micropores to the thickness of the active material layer is A, where A satisfies: 0.5 ≤ A ≤ 0.7.

[0029] In some embodiments, along the length of the first electrode, a first distance E1 exists between one end edge of the active material layer and the nearest polygonal micropore thereto, and a second distance E2 exists between the other end edge of the active material layer and the nearest polygonal micropore thereto, wherein E1 and E2 satisfy: 0 ≤ E1 ≤ 12 mm, 0 ≤ E2 ≤ 12 mm; and / or,

[0030] In the width direction of the first electrode, there is a third spacing E3 between one edge of the active material layer and the nearest polygonal micropore there is a fourth spacing E4 between the other edge of the active material layer and the nearest polygonal micropore there is, wherein E3 and E4 satisfy: 0≤E3≤3mm, 0≤E4≤3mm.

[0031] This application also proposes an electronic device comprising any of the electrochemical devices described herein.

[0032] The electrochemical device of this application features a perforated region in the active material layer of the electrode. This perforated region contains multiple spaced polygonal micropores with a pore size D ranging from 3 μm to 50 μm. These polygons achieve near-seamless packing within a unit area, with equal distances from their vertices to the center and uniform minimum spacing between adjacent micropores. This results in a higher density of polygonal micropores compared to 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 polygon to the center is smaller than the radius of a circle, and the transport channels formed between adjacent micropores are distributed in a regular grid pattern, ions can traverse the micropore array along a shorter straight-line distance when passing through the perforated region. Compared to the dispersed transport path formed by circular micropores, the ion diffusion path is shorter, thus improving ion diffusion efficiency. Attached Figure Description

[0033] The embodiments described in this application are not limited to the accompanying drawings, which are only some of the embodiments described herein. Those skilled in the art can obtain drawings of other embodiments based on the content of this application.

[0034] Figure 1 This is a schematic diagram of the electrode assembly of an electrochemical device in one embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of the first electrode of the electrode assembly of the electrochemical device in one embodiment of this application;

[0036] Figure 3 This is a schematic diagram of the structure of the first electrode of the electrode assembly of the electrochemical device in another embodiment of this application;

[0037] Figure 4 for Figure 3 A schematic diagram of the perforated area in the embodiment;

[0038] Figure 5 This is a schematic diagram of the structure of the first electrode of the electrode assembly of the electrochemical device in another embodiment of this application;

[0039] Figure 6 for Figure 5 A schematic diagram of the perforated area in the embodiment;

[0040] Figure 7 This is a schematic diagram of the structure of the first electrode of the electrode assembly of the electrochemical device in another embodiment of this application;

[0041] Figure 8 for Figure 7 A schematic diagram of the perforated area in the embodiment;

[0042] Figure 9 This is a schematic diagram of the structure of the first electrode of the electrode assembly of the electrochemical device in another embodiment of this application;

[0043] Figure 10 for Figure 9 A schematic diagram of the perforated area in the embodiment;

[0044] Figure 11 This is a schematic diagram of a portion of the active material layer of the first electrode in one embodiment of this application;

[0045] Figure 12 This is a schematic diagram of the structure of another part of the active material layer of the first electrode in one embodiment of this application;

[0046] Figure 13 This is a schematic diagram of a portion of the active material layer of the first electrode in another embodiment of this application;

[0047] Explanation of icon numbers:

[0048]

[0049]

[0050] 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

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. The embodiments of this application may omit unnecessary detailed descriptions. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0052] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0053] In the following description, all figures disclosed in this application are approximations.

[0054] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the present application.

[0055] This application discloses an electrochemical device, referring to... Figure 1 and Figure 2 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.

[0056] The first electrode 100 includes a current collector 110 and an active material layer 120 disposed on the current collector 110. The active material layer 120 has a perforated area 121 along the length direction of the first electrode 100. The perforated area 121 has a plurality of spaced polygonal micropores 122. The pore size of the polygonal micropores 122 is D, and D satisfies: 3μm≤D≤50μm.

[0057] The electrochemical device involved in this application includes 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.

[0058] like Figure 1As 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 an anode (or negative electrode), and the second electrode 300 can be a cathode (or positive electrode). The separator 200 is located between the anode and cathode electrodes, playing a crucial role in isolating the positive and negative electrodes and preventing direct contact and short circuits, while simultaneously allowing lithium ions to pass through, ensuring the smooth progress of the electrochemical reaction. In other embodiments, the first electrode 100 can be the cathode, and the second electrode 300 can be the anode.

[0059] In addition to the electrode assembly, the electrochemical device may also include a housing, within which the electrode assembly is encapsulated. Furthermore, the housing contains an electrolyte that serves as a carrier for ion transport, forming a conductive path between the anode and cathode to ensure the directional migration of ions during charging and discharging. Depending on the application, the housing may be made of aluminum-plastic film (for pouch cells) or a metal casing (for cylindrical / square hard-case cells) to ensure the device's sealing performance and prevent electrolyte leakage.

[0060] The first electrode 100 includes a current collector 110 and an active material layer 120, with the active material layer 120 disposed on the current collector 110. Taking the first electrode 100 as an anode electrode as an example, its current collector 110 can be a metal foil or a composite current collector 110, and its active material layer 120 is made of an anode active material. The second electrode 300 also includes a current collector 110 and an active material layer 120 corresponding to its polarity, but the materials used for the current collector 110 and active material layer 120 of the first electrode 100 are different. Specifically, the current collector 110 of the first electrode 100 has a first surface and a second surface opposite to each other along its thickness direction, and the active material layer 120 can be selectively disposed on the first surface, the second surface, or both surfaces of the current collector 110. Furthermore, the active material layer 120 on the first surface and / or the second surface of the current collector 110 may have perforated areas 121.

[0061] Multiple polygonal micropores 122 are processed within the perforated area 121. These polygonal micropores 122 can be arranged in an array, for example, the perforated area 121 has m rows and n columns of polygonal micropores 122. The polygonal micropores 122 are regular polygons, including regular hexagons, regular pentagons, squares, equilateral triangles, etc., with regular hexagons being the most preferred. Regular hexagonal micropores have the characteristic of "seamless close-packing," where the edges of adjacent regular hexagonal micropores can fit together without any close-packing gaps. Furthermore, 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 ensures that the minimum spacing between adjacent micropores is consistent and avoids local ion transport congestion.

[0062] The aperture D of the polygonal micro-hole 122 (defined as the diameter of the circumcircle of the polygon) is 3μm to 50μm. For example, the aperture D of the polygonal micro-hole 122 can be 3μm, 6μm, 9μm, ..., 20μm, 23μm, 26μm, ..., 40μm, 43μm, 46μm, 49μm or 50μm, or within the range of any two of the above values.

[0063] The electrochemical device of this application has a perforated region 121 in the active material layer 120 of the electrode. The perforated region 121 has a plurality of spaced polygonal micropores 122. The pore diameter D of the polygonal micropores 122 is 3μm to 50μm. The polygons can achieve almost seamless close packing in a unit area in the plane. The distance from their vertices to the center is equal and the minimum spacing between adjacent micropores is uniform. This makes the arrangement density of polygonal micropores 122 greater than that of circular micropores within the same area of ​​the perforated region 121, 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 polygon to the center is smaller than the radius of the circle, and the transport channels formed between adjacent micropores are distributed in a regular grid pattern, ions can pass through the micropore array along a shorter straight-line distance when passing through the perforated region 121. Compared with the dispersed transport path formed by circular micropores, the ion diffusion path is shorter, which can improve the ion diffusion efficiency.

[0064] Option 1:

[0065] In some implementations, refer to Figure 3 and Figure 4 There are multiple perforated areas 121, and the multiple perforated areas 121 are distributed sequentially along the length direction of the first electrode 100;

[0066] The active material layer 120 is provided with a groove 120C for exposing a portion of the surface of the current collector 110 to connect to the tab. The plurality of perforated areas 121 include a third perforated area 1213, which covers the groove 120C. The diameter of the polygonal micropores 122 in the third perforated area 1213 is not equal to the diameter of the polygonal micropores 122 in at least a portion of the other perforated areas 121.

[0067] Along the length of the first electrode 100, the active material layer 120 is divided into multiple independent perforated areas 121. These perforated areas 121 can be located on the first and / or second surfaces of the current collector 110. The multiple perforated areas 121 are sequentially distributed along the length of the first electrode 100 (adjacent perforated areas 121 can be seamlessly connected or spaced apart). The dimensional parameters of different perforated areas 121, such as region length, region width, and region area, can be equal or unequal, depending on actual requirements. Each perforated area 121 contains multiple polygonal micropores 122.

[0068] The active material layer 120 on the first and / or second surfaces of the current collector 110 is provided with a groove 120C. The groove 120C, also known as the tab mounting groove, penetrates the active material layer 120 along its thickness direction, exposing a portion of the surface of the current collector 110. The size of the groove 120C is adapted to the tab (which matches the polarity of the first electrode 100). The tab can be embedded in the groove 120C and connected to the current collector 110 to achieve current conduction / conduction. The connection method can be welding (such as laser welding, ultrasonic welding), etc., including but not limited to these methods. The groove 120C can be located at the middle position of the first electrode 100 along its length direction, and the tab can be installed therein, forming a centrally located tab structure. The location of the groove 120C includes, but is not limited to, this method.

[0069] The plurality of perforated areas 121 include a third perforated area 1213 and other perforated areas other than the third perforated area 1213. The third perforated area 1213 covers and extends beyond the corresponding area (i.e., the tab connection area) of the active material layer 120 where the groove 120C is located, and the pore diameter of the polygonal micropores 122 in the third perforated area 1213 is not equal to the pore diameter of the polygonal micropores 122 in at least a portion of the other perforated areas 121.

[0070] The diameter of the polygonal micropores 122 in the third perforated area 1213 at the tab connection region of the active material layer 120 can be different from the diameter of the polygonal micropores 122 in a portion of the other perforated areas 121, or it can be different from the diameter of the polygonal micropores 122 in all the other perforated areas 121. For example, if there are three perforated areas 121, and the third perforated area 1213 is located in the tab region, the diameter of the polygonal micropores 122 in the third perforated area 1213 can be different from the diameter of the polygonal micropores 122 in one of the other two perforated areas 121, or it can be different from the diameter of the polygonal micropores 122 in both of the other two perforated areas 121.

[0071] The perforated area 121 involved can be a virtual area. In the actual electrode structure, the boundary of each perforated area 121 in the electrode length direction is not defined by a clear mark or boundary line on the electrode, but can be determined by other features. For example, depending on the designed different scribing spacing, multiple polygonal micro-holes 122 with the same scribing spacing can form a polygonal micro-hole group. The polygonal micro-holes 122 at both ends of the polygonal micro-hole group can be used as the boundary of the perforated area 121 in the electrode length direction, or a preset distance (such as 1 mm) can be extended outward from the polygonal micro-holes 122 at both ends of the polygonal micro-hole group as the boundary of the perforated area 121 in the electrode length direction.

[0072] During the charging and discharging process of the electrochemical device, the current is introduced into / out of 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 the edge of the electrode, resulting in a distribution characteristic of "high in the tab area and low in the edge area" of the current density on the electrode surface. 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 lithium ion consumption / generation rate is fast near the tab and the concentration requirement is high, while the edge area is the opposite.

[0073] This implementation method achieves a partitioned gradient design based on the aperture of the polygonal micro-hole 122. The specific mechanism of action can be as follows:

[0074] The area corresponding to the tab: This area is designed with polygonal micropores 122 to maximize the area ratio of the polygonal micropores 122 per unit area, providing a larger area of ​​three-dimensional through-hole ion transport channels. During charging and discharging, the large area of ​​polygonal micropores 122 can quickly conduct a large number of lithium ions, meeting the ion transport requirements under high current density near the tab, avoiding "concentration polarization" (i.e., the lithium ion concentration difference between the active material surface and the electrolyte) caused by ion congestion, thereby reducing the electrochemical polarization overpotential and improving charging and discharging efficiency.

[0075] Non-tab region: As the distance from the tab decreases, the required current density and lithium-ion concentration gradually decrease. By changing the pore size of the polygonal micropore 122 to reduce the area ratio of the polygonal micropore 122, the electrolyte waste caused by channel vacancy and the destruction of the structural integrity of the active material layer 120 can be avoided while meeting the ion transport requirements (larger polygonal micropores 122 will reduce the mechanical strength of the active material layer 120).

[0076] Through a zoned gradient design, the supply of ion transport channels on the electrode surface is precisely matched with the demand in different areas. During charging, external current enters the current collector 110 through the tabs, and the large-area polygonal micropores 122 accelerate the migration of lithium ions from the electrolyte to the interior of the active material layer 120, ensuring that the active material near the tabs quickly receives lithium ions; in other areas, the polygonal micropores 122 of a reasonable area are designed to prevent lithium ions from being retained in the channels, ensuring a balanced overall migration rate.

[0077] In other words, the electrode adopts a partitioned perforation design and the pore size of the polygonal micropores 122 between the partitions is different. The ion transport channel area is large in the tab area and relatively small in the other areas. This can match the current and ion concentration distribution characteristics on the electrode surface, achieve the matching and balance of ion transport channel supply and demand, and help improve the performance of electrochemical devices.

[0078] As an auxiliary scheme, the spacing between the polygonal micro-holes 122 in the third perforation area 1213 is not greater than the spacing between the polygonal micro-holes 122 in at least a portion of the remaining perforation areas 121.

[0079] The spacing between the polygonal micropores 122 in the third perforated area 1213 corresponding to the tab connection region of the active material layer 120 can be no greater than the spacing between the polygonal micropores 122 in a portion of the other perforated areas 121, or no greater than the spacing between the polygonal micropores 122 in all the other perforated areas 121. The described spacing is the distance between the edges of two adjacent polygonal micropores 122 along the length or width direction of the first electrode 100, or in other directions. Optionally, for each perforated area 121, the spacing between any two adjacent polygonal micropores 122 within the area is equal. This equality can be completely equal or approximately equal, allowing for slight errors.

[0080] In some implementations, refer to Figure 3 and Figure 4 The multiple perforated areas 121 also include a first perforated area 1211 and a second perforated area 1212, and the first perforated area 1211, the second perforated area 1212 and the third perforated area 1213 are distributed sequentially along the length direction of the first electrode 100.

[0081] In the first perforated zone 1211, the polygonal micropores 122 have a pore diameter of D1 and a pore pitch of L1; in the second perforated zone 1212, the polygonal micropores 122 have a pore diameter of D2 and a pore pitch of L2; in the third perforated zone 1213, the polygonal micropores 122 have a pore diameter of D3 and a pore pitch of L3. D1, D2 and D3 satisfy: D1<D2<D3, and L1, L2 and L3 satisfy: L1=L2=L3.

[0082] Specifically, among the multiple perforated zones 121 divided on the active material layer 120 of the first pole piece 100, the first perforated zone 1211, the second perforated zone 1212, and the third perforated zone 1213 are arranged in sequence along the length direction of the first pole piece 100. For example, from the edge position at one end of the pole piece (such as the winding finishing end / outermost end) to the tab position, the sequence is the first perforated zone 1211 → the second perforated zone 1212 → the third perforated zone 1213, and adjacent perforated zones 121 are seamlessly connected (or arranged at intervals).

[0083] The third perforated zone 1213 covers the region of the active material layer 120 where the groove 120C is located (that is, directly corresponding to the exposed region of the current collector 110 connected to the tab), and ensures that the high-current region around the tab is covered by a large area of polygonal micropores 122. It is easy to understand that in a unit area, with the same pore pitch, the larger the pore diameter, the larger the area ratio of the polygonal micropores 122.

[0084] It is set that the pore diameters of the polygonal micropores 122 in the first perforated zone 1211, the second perforated zone 1212 and the third perforated zone 1213 are respectively D1, D2 and D3, and the pore pitches are respectively L1, L2 and L3, which satisfy D1>D2>D3 and L1>L2>L3. The specific parameters need to be designed in combination with the current density distribution on the surface of the pole piece, following the principle that the current density is positively correlated with the area ratio of the polygonal micropores 122.

[0085] The core principle of this embodiment lies in that the gradient ion transport channels adapt to the current density gradient. Through the equal design of the pore pitches of the polygonal micropores 122 where L1=L2=L3 and the pore diameter difference design of the polygonal micropores 122 where D1<D2<D3, the area of the ion transport channels on the surface of the pole piece increases progressively from the edge of one end (such as the winding finishing end / outermost end) to the tab, which accurately matches the distribution characteristic of current density from low to high.

[0086] During the charging and discharging process of the electrochemical device, when the current is transmitted from the tab (the position corresponding to the third perforation area 1213) to the edge of the electrode (the first perforation area 1211), the voltage drop caused by the resistance of the current collector 110 causes the current density to decrease in a stepwise manner, and the corresponding lithium-ion demand also shows a gradient distribution. The third perforation area 1213 needs to transmit lithium ions quickly to match the insertion / deintercalation reaction under high current, while the second perforation area 1212 serves as a buffer area to make a smooth transition, effectively preventing sudden current changes and related side reactions. The first perforation area 1211 only needs a small amount of lithium ions to meet the low current demand.

[0087] The specific ion transport mechanisms in each perforated area are as follows:

[0088] The hole spacing L1 of the polygonal micro-holes 122 in the first punching area 1211, the hole spacing L2 of the polygonal micro-holes 122 in the second punching area 1212, and the hole spacing L2 of the polygonal micro-holes 122 in the third punching area 1213 are equal.

[0089] Among them, the polygonal micropores 122 in the third perforated area 1213 have the largest pore size D3 and the largest area ratio in the region, forming a three-dimensional ion channel with a high area ratio. During charging, lithium ions in the electrolyte can quickly penetrate into the active material layer 120 through the large-area polygonal micropores 122, avoiding concentration polarization near the tabs due to insufficient ion supply; during discharging, lithium ions released from the active material can quickly enter the electrolyte through the large-area polygonal micropores 122, reducing the residence time of lithium ions in the active material layer 120.

[0090] In the second perforated region 1212, the diameter D2 of the polygonal micropores 122 is centered, and the area of ​​the polygonal micropores 122 in this region is of moderate proportion. This avoids both insufficient channel area in the third perforated region 1213 and excessive channel area in the first perforated region 1211. This region acts as a buffer zone for ion transport, smoothly connecting the ion transport rates of the third perforated region 1213 and the first perforated region 1211, preventing ion congestion or vacancy caused by abrupt changes in transport rates between adjacent regions.

[0091] In the first perforated area 1211, the pore size D1 of the polygonal micropores 122 is the smallest, and the area ratio of the polygonal micropores 122 in the area is the smallest. While meeting the requirements of low current density ion transport, it minimizes the ineffective perforation area of ​​the active material layer 120 and avoids the destruction of the structural integrity of the active material layer 120 due to excessive perforation area.

[0092] Furthermore, the number of punched areas 121 can be designed to be five, for example:

[0093] In some implementations, refer to Figures 3 to 6The perforated area 121 also includes a fourth perforated area 1214 and a fifth perforated area 1215. The first perforated area 1211, the second perforated area 1212, the third perforated area 1213, the fourth perforated area 1214 and the fifth perforated area 1215 are distributed sequentially along the length direction of the first electrode 100.

[0094] In the fourth punching area 1214, the diameter of the polygonal micro-hole 122 is D4 and the spacing between the holes is L4. In the fifth punching area 1215, the diameter of the polygonal micro-hole 122 is D5 and the spacing between the holes is L5. D3, D4, and D5 satisfy: D3≥D4≥D5, and L3, L4, and L5 satisfy: L3=L4=L5.

[0095] Specifically, the fourth perforation area 1214 and the fifth perforation area 1215 are connected to the third perforation area 1213 and are arranged sequentially along the length of the first electrode 100. For example, from the edge of one end of the electrode (such as the winding end / outermost end) through the tab to the edge of the other end (such as the winding start end / innermost end), the order is: first perforation area 1211 → second perforation area 1212 → third perforation area 1213 → fourth perforation area 1214 → fifth perforation area 1215. Adjacent perforation areas 121 are seamlessly connected (or spaced apart).

[0096] Let the diameters of the polygonal micro-holes 122 in the fourth perforation area 1214 and the fifth perforation area 1215 be D4 and D5, respectively, and the hole spacings be L3 and L4, respectively. These parameters correspond to the diameter D3 and hole spacing L3 of the polygonal micro-holes 122 in the third perforation area 1213, satisfying D3≥D4≥D5 and L3=L4=L5. The specific parameters need to be designed in conjunction with the current density distribution on the electrode surface, following the principle that the current density is positively correlated with the area ratio of the polygonal micro-holes 122.

[0097] For example, such as Figure 3 and Figure 4 As shown, for electrochemical devices with general negative electrode systems, the following scheme can be adopted when drilling holes on the electrode surface: D3, D4, and D5 satisfy: D3>D4>D5.

[0098] The core principle of this implementation lies in the gradient ion transport channel adapting to the current density gradient. By designing equal spacing between L3=L4=L5 polygonal micropores 122 and different apertures of D3>D4>D5 polygonal micropores 122, the ion transport channel area on the electrode surface increases from the edge of the other end (such as the starting end / innermost end of the winding) to the tab, accurately matching the distribution characteristics of current density from low to high.

[0099] During the charging and discharging process of the electrochemical device, when the current is transmitted from the tab (corresponding to the third perforation area 1213) to the edge of the electrode (the fifth perforation area 1215), the voltage drop caused by the resistance of the current collector 110 causes the current density to decrease in a stepwise manner, and the corresponding lithium-ion demand also shows a gradient distribution. The third perforation area 1213 needs to transmit lithium-ions quickly to match the insertion / deintercalation reaction under high current, while the fourth perforation area 1214 serves as a buffer area to make a smooth transition, effectively preventing sudden current changes and related side reactions. The fifth perforation area 1215 only needs a small amount of lithium-ions to meet the low current demand.

[0100] The specific ion transport mechanisms in each perforated area are as follows:

[0101] The hole spacing L3 of the polygonal micro-holes 122 in the third drilling area 1213, the hole spacing L4 of the polygonal micro-holes 122 in the fourth drilling area 1214, and the hole spacing L of the polygonal micro-holes 122 in the fifth drilling area 1215. a equal.

[0102] In the third perforated area 1213, the polygonal micropores 122 have the largest pore size D3 and the largest area ratio within the area, forming a three-dimensional ion channel with a high area ratio. During charging, lithium ions in the electrolyte can quickly penetrate into the active material layer 120 through the large-area polygonal micropores 122, avoiding concentration polarization near the tabs due to insufficient ion supply. During discharging, lithium ions released from the active material can quickly enter the electrolyte through the large-area polygonal micropores 122, reducing the residence time of lithium ions in the active material layer 120.

[0103] In the fourth perforated region 1214, the diameter D4 of the polygonal micropores 122 is centered, and the area of ​​the polygonal micropores 122 in this region is of moderate proportion. This avoids both insufficient channel area in the third perforated region 1213 and excessive channel area in the fifth perforated region 1215. This region acts as a buffer zone for ion transport, smoothly connecting the ion transport rates of the third perforated region 1213 and the fifth perforated region 1215, preventing ion congestion or vacancy caused by abrupt changes in transport rates between adjacent regions.

[0104] In the fifth perforation zone 1215, the pore size D5 of the polygonal micropore 122 is the smallest, and the area of ​​the polygonal micropore 122 in the zone is the smallest. While meeting the requirements of low current density ion transport, it minimizes the ineffective perforation area of ​​the active material layer 120 and avoids the destruction of the structural integrity of the active material layer 120 due to excessive perforation area.

[0105] In addition, the use of high-silicon anode systems in electrochemical devices is an important direction for improving energy density, but the lithium plating problem directly affects the safety and lifespan of the battery. Although high-silicon anode systems in electrochemical devices can significantly improve energy density, they are prone to lithium plating (metallic lithium depositing on the anode surface) during charge and discharge. This is mainly due to the large volume change of silicon materials, the unstable solid-electrolyte interface (SEI), and the relatively slow lithium-ion diffusion kinetics. Among them, after the electrode and separator are wound together to form a core using a high-silicon anode system, lithium plating is particularly severe on the tab side of the electrode (i.e., the wound portion from the tab inwards).

[0106] Therefore, for electrochemical devices with high-silicon systems (including but not limited to these), the following approach can be used when drilling holes on the electrode surface:

[0107] In some implementations, refer to Figure 5 and Figure 6 , D3, D4 and D5 satisfy: D3=D4=D5.

[0108] This embodiment is a customized design scheme for an electrochemical device with a high silicon anode system. The core is that the third, fourth and fifth perforation regions 1215 adopt polygonal micropores 122 with the same pore size, while only the pore size of the polygonal micropores 122 in the first and second perforation regions 1212 maintains a gradient change.

[0109] The punched area distribution logic adapts to the winding structure of a soft-pack battery:

[0110] The arrangement sequence is as follows: first perforation area 1211 (outer layer) → second perforation area 1212 (middle layer, first transition area) → third perforation area 1213 (inner layer, tab connection area) → fourth perforation area 1214 (inner layer, second transition area) → fifth perforation area 1215 (inner layer); among which, the third, fourth and fifth perforation areas 1215 cover the tab and the high-risk area of ​​lithium plating on one side.

[0111] Due to the tab current collection effect and concentrated winding pressure in the inner layer (third-fifth perforated areas 1215), and the slow lithium-ion diffusion of high-silicon materials, a large-area ion transport channel is required. By using a D3=D4=D5 design, a high area ratio of ion transport channels is maintained throughout the inner layer region, effectively improving ion diffusion efficiency and reducing lithium plating.

[0112] In some implementations, D1, D2, D3, D4, and D5 also satisfy the following: 3μm≤D1≤25μm, 15μm≤D2≤35μm, 30μm≤D3≤50μm, 3μm≤D4≤50μm, and 3μm≤D5≤50μm;

[0113] L1, L2, L3, L4, and L5 also satisfy the following condition: 6μm≤L1=L2=L3=L4=L5≤150μm.

[0114] In addition to Option 1 mentioned above, Option 2 can also be adopted, as detailed below:

[0115] In some implementations, refer to Figure 7 and Figure 8 The multiple perforated areas 121 also include a first perforated area 1211 and a second perforated area 1212, and the first perforated area 1211, the second perforated area 1212 and the third perforated area 1213 are distributed sequentially along the length direction of the first electrode 100.

[0116] The diameter of the polygonal micro-hole 122 in the first punching area 1211 is D1 and the spacing between the holes is L1. The diameter of the polygonal micro-hole 122 in the second punching area 1212 is D2 and the spacing between the holes is L2. The diameter of the polygonal micro-hole 122 in the third punching area 1213 is D3 and the spacing between the holes is L3. D1, D2, and D3 satisfy: D1>D2>D3, and L1, L2, and L3 satisfy: L1>L2>L3.

[0117] The location and layout of the perforated area 121 are consistent with Scheme 1, as detailed above. It is easy to understand that within a unit area, the smaller the hole spacing and hole diameter, the larger the area proportion of the polygonal micro-holes 122.

[0118] Let the diameters of the polygonal micro-holes 122 in the first perforation area 1211, the second perforation area 1212, and the third perforation area 1213 be D1, D2, and D3, respectively, and the hole spacings be L1, L2, and L3, respectively, satisfying D1>D2>D3 and L1>L2>L3. Specific parameters need to be designed in conjunction with the current density distribution on the electrode surface, following the principle that current density is positively correlated with the area ratio of the polygonal micro-holes 122.

[0119] The core principle of this implementation lies in the gradient ion transport channel adapting to the current density gradient. By designing the pore spacing and pore size differences of polygonal micropores 122 with L1>L2>L3 and D1>D2>D3, the ion transport channel area on the electrode surface increases from one end (such as the winding end / outermost end) to the tab, accurately matching the distribution characteristics of current density from low to high.

[0120] The current density distribution phenomenon on the electrode surface during the charging and discharging process of the electrochemical device can be found in the relevant description in Scheme 1, and will not be elaborated here.

[0121] The specific ion transport mechanisms in each perforated area are as follows:

[0122] In the third perforated area 1213, the polygonal micropores 122 have the smallest pore diameter D3 and the smallest inter-pore spacing L3. This region exhibits the highest density and largest area ratio of polygonal micropores 122, forming a dense three-dimensional ion channel with a high area ratio. During charging, lithium ions in the electrolyte can rapidly penetrate into the active material layer 120 through the large-area, dense polygonal micropores 122, preventing concentration polarization near the electrode due to insufficient ion supply. During discharging, lithium ions released from the active material can rapidly enter the electrolyte through the large-area, dense polygonal micropores 122, reducing the residence time of lithium ions within the active material layer 120.

[0123] In the second perforated region 1212, the diameter D2 and the spacing L2 of the polygonal micropores 122 are centered. The density and area ratio of the polygonal micropores 122 in this region are moderate, which avoids both insufficient channel area in the third perforated region 1213 and excessive channel area in the first perforated region 1211. This region acts as a buffer zone for ion transport, which can smoothly connect the ion transport rates of the third perforated region 1213 and the first perforated region 1211, preventing ion congestion or vacancy caused by abrupt changes in transport rates between adjacent regions.

[0124] In the first perforated area 1211, the polygonal micropores 122 have the largest aperture D1 and the largest spacing L1. The polygonal micropores 122 have the smallest density and the smallest area ratio in the area. While meeting the requirements of low current density ion transport, the ineffective perforation area of ​​the active material layer 120 is minimized, and the structural integrity of the active material layer 120 is avoided from being damaged due to excessive perforation area.

[0125] Furthermore, the number of punched areas 121 can be designed to be five, for example:

[0126] In some implementations, refer to Figures 7 to 10 The multiple perforated areas 121 also include a fourth perforated area 1214 and a fifth perforated area 1215. The first perforated area 1211, the second perforated area 1212, the third perforated area 1213, the fourth perforated area 1214 and the fifth perforated area 1215 are distributed sequentially along the length direction of the first electrode 100.

[0127] In the fourth punching area 1214, the diameter of the polygonal micro-hole 122 is D4 and the spacing between the holes is L4. In the fifth punching area 1215, the diameter of the polygonal micro-hole 122 is D5 and the spacing between the holes is L5. D3, D4, and D5 satisfy: D3≤D4≤D5, and L3, L4, and L5 satisfy: L3 <L4<L5。

[0128] Specifically, the fourth perforated region 1214 and the fifth perforated region 1215 are connected to the third perforated region 1213 and arranged sequentially along the length direction of the first pole piece 100. For example, from the edge position at one end of the pole piece (such as the winding finishing end / outermost end) through the tab position to the edge position at the other end (such as the winding starting end / innermost end), the sequence is the first perforated region 1211 → the second perforated region 1212 → the third perforated region 1213 → the fourth perforated region 1214 → the fifth perforated region 1215, and adjacent perforated regions 121 are seamlessly connected (or arranged at intervals). The third perforated region 1213 correspondingly covers and extends beyond the region of the active material layer 120 where the groove 120C is located (that is, directly corresponding to the exposed region of the current collector 110 connected to the tab).

[0129] Let the pore diameters of the polygonal micropores 122 in the fourth perforated region 1214 and the fifth perforated region 1215 be D4 and D5 respectively, and the pore spacings be L3 and L4 respectively, which correspondingly satisfy D3≤D4≤D5 and L3<L4<L5 in relation to the pore diameter D3 and pore spacing L3 of the polygonal micropores 122 in the third perforated region 1213. The specific parameters need to be designed in combination with the current density distribution on the surface of the pole piece, following the principle that the current density is positively correlated with the area proportion of the polygonal micropores 122.

[0130] For example, as Figure 7 and Figure 8 shown, for the electrochemical device of a general negative electrode system, the following scheme can be adopted when perforating the surface of its pole piece: D3, D4 and D5 satisfy: D3<D4<D5.

[0131] The core principle of this embodiment lies in that the gradient ion transport channels adapt to the current density gradient. Through the design of the difference in pore spacing and pore diameter of the polygonal micropores 122 with L3<L4<L5 and D3<D4<D5, the area of the ion transport channels on the surface of the pole piece increases progressively from the edge of the other end (such as the winding starting end / innermost end) to the tab, which accurately matches the distribution characteristic of current density from low to high.

[0132] For the phenomenon of current density distribution on the surface of the pole piece during the charging and discharging process of the electrochemical device, reference may be made to the first scheme, which will not be described in detail here.

[0133] The ion transport mechanism of each perforated region is specifically as follows:

[0134] In the third perforated area 1213, the polygonal micropores 122 have the smallest pore diameter D3 and the smallest inter-pore spacing L3. This region exhibits the highest density and largest area ratio of polygonal micropores 122, forming a dense three-dimensional ion channel with a high area ratio. During charging, lithium ions in the electrolyte can rapidly penetrate into the active material layer 120 through the large-area, dense polygonal micropores 122, preventing concentration polarization near the electrode due to insufficient ion supply. During discharging, lithium ions released from the active material can rapidly enter the electrolyte through the large-area, dense polygonal micropores 122, reducing the residence time of lithium ions within the active material layer 120.

[0135] In the fourth perforated region 1214, the diameter D4 and the spacing L4 of the polygonal micropores 122 are centered. The density and area ratio of the polygonal micropores 122 in this region are moderate, which avoids both insufficient channel area in the third perforated region 1213 and excessive channel area in the fifth perforated region 1215. This region acts as a buffer zone for ion transport, smoothly connecting the ion transport rates of the third perforated region 1213 and the fifth perforated region 1215, preventing ion congestion or vacancy caused by abrupt changes in transport rates between adjacent regions.

[0136] In the fifth perforation zone 1215, the polygonal micropores 122 have the largest pore diameter D5 and the largest pore spacing L5. The polygonal micropores 122 have the smallest density and the smallest area ratio in the region. While meeting the requirements of low current density ion transport, the ineffective perforation area of ​​the active material layer 120 is minimized, and the structural integrity of the active material layer 120 is avoided from being damaged due to excessive perforation area.

[0137] For electrochemical devices with high-silicon systems (including but not limited to these), the following approach can be used when drilling holes on the electrode surface:

[0138] In some implementations, refer to Figure 9 and Figure 10 , D3, D4 and D5 satisfy: D3=D4=D5.

[0139] This embodiment is a customized design scheme for electrochemical devices with high silicon anode systems. The core is that the third, fourth and fifth perforation regions 1215 adopt polygonal micropores 122 with the same aperture. Only the aperture of the polygonal micropores 122 in the first and second perforation regions 1212 maintains a gradient change. The relevant content of the perforation region distribution logic adapting to the soft-pack battery winding structure can be found in Scheme 1, and will not be described in detail here.

[0140] The punched area distribution logic adapts to the winding structure of a soft-pack battery:

[0141] The arrangement sequence is: first perforated zone 1211 (outer winding layer) → second perforated zone 1212 (middle winding layer, first transition zone) → third perforated zone 1213 (inner winding layer, tab connection zone) → fourth perforated zone 1214 (inner winding layer, second transition zone) → fifth perforated zone 1215 (inner winding layer); wherein the third, fourth and fifth perforated zones 1215 cover the tab and the high lithium deposition risk zone on one side thereof.

[0142] The inner winding layer (third to fifth perforated zones 1215) is subject to the tab current collecting effect and winding pressure concentration, and the high-silicon material has slow lithium ion diffusion, so a continuous large-area high-density ion transmission channel is required. Through the design of D3=D4=D5, the inner layer area maintains dense ion transmission channels with a high area ratio, which effectively improves the ion diffusion efficiency and reduces the lithium deposition phenomenon.

[0143] In some embodiments, D1, D2, D3, D4, and D5 further satisfy: 30μm≤D1≤50μm, 15μm≤D2≤35μm, 3μm≤D3≤25μm, 3μm≤D4≤50μm, 3μm≤D5≤50μm;

[0144] L1, L2, L3, L4, and L5 further satisfy: 100μm≤L1≤150μm, 55μm≤L2≤115μm, 6μm≤L3≤65μm, 6μm≤L4≤150μm, 6μm≤L5≤150μm.

[0145] In some embodiments, with reference to Figures 11 to 13 , the hole depth of the polygonal micro-holes 122 in the first perforated zone 1211 is H1, the hole depth of the polygonal micro-holes 122 in the second perforated zone 1212 is H2, the hole depth of the polygonal micro-holes 122 in the third perforated zone 1213 is H3, the hole depth of the polygonal micro-holes 122 in the fourth perforated zone 1214 is H4, the hole depth of the polygonal micro-holes 122 in the fifth perforated zone 1215 is H5, and H1, H2, H3, H4, H5 satisfy: H1<H2<H3, and H3≥H4≥H5.

[0146] This embodiment is a dimensional upgrade of the five-scoring-zone scheme for the electrode sheet, which superimposes groove depth gradient control on the basis of the aforementioned pore diameter and perforation pitch design. Through the coordination of the groove depth gradient with the pore diameter and perforation pitch gradients, it adapts to the distribution characteristic of the current density increasing first and then gradually decreasing along the length direction of the electrode sheet. Wherein, the groove depth of the first to third perforated zones 1213 increases progressively, and the groove depth of the third to fifth perforated zones 1215 remains at a high value or decreases gently.

[0147] Let the depths of the polygonal micro-holes 122 in the first drilling area 1211, the second drilling area 1212, the third drilling area 1213, the fourth drilling area 1214, and the fifth drilling area 1215 be H1, H2, H3, H4, and H5, respectively. The specific parameters need to be designed in conjunction with the current density distribution on the electrode surface, following the principle that the current density is positively correlated with the depth of the polygonal micro-holes 122.

[0148] Since the pore depth determines the ion transport capacity of a single polygonal micropore 122, and the pore diameter and perforation spacing determine the area ratio of the polygonal micropore 122, the combination of the two forms the total ion channel capacity per unit area. The core principle of this implementation is also based on gradient ion transport channels adapted to current density gradients. Through a pore depth difference design of H1 < H2 < H3, the pore depth of the ion transport channel increases from one end (e.g., the winding end / outermost end) of the electrode surface to the tab, improving channel transport capacity and precisely matching the distribution characteristics of current density from low to high. Furthermore, through a pore depth difference or equal design of H3 ≥ H4 ≥ H5, the pore depth of the ion transport channel decreases or remains the same from the tab to the other end (e.g., the winding start end / innermost end) of the electrode surface, precisely matching the distribution characteristics of current density from high to low or the same. The synergistic effect of the pore depth, pore diameter, and scribe spacing of the polygonal micropores creates multiple gradient optimizations. The total channel capacity per unit area changes synchronously with the current density, with no areas of excess or deficiency. This can further achieve the matching and balance of supply and demand for ion transport channels, which helps to improve the performance of electrochemical devices.

[0149] For electrochemical devices with general negative electrode systems, the following approach can be used when drilling holes on the electrode surface:

[0150] In some implementations, refer to Figure 12 H3, H4, and H5 satisfy the condition: H3 > H4 > H5.

[0151] The specific ion transport mechanism of each perforated region 121 is as follows:

[0152] The polygonal micropores 122 in the third perforated area 1213 have the largest pore depth H3 and the largest total capacity within the area, forming a large-volume three-dimensional ion channel. During charging, lithium ions in the electrolyte can quickly penetrate into the active material layer 120 through the deeper polygonal micropores 122, avoiding concentration polarization near the tabs due to insufficient ion supply. During discharging, lithium ions released from the active material can quickly enter the electrolyte through the deeper polygonal micropores 122, reducing the residence time of lithium ions in the active material layer 120.

[0153] The depth H4 of the polygonal micropores 122 in the fourth perforation zone 1214 is centered, and the total capacity of the polygonal micropores 122 in the region is moderate. This avoids both insufficient channel capacity in the third perforation zone 1213 and excessive channel capacity in the fifth perforation zone 1215. This region acts as a buffer zone for ion transport, smoothly connecting the ion transport rates of the third perforation zone 1213 and the fifth perforation zone 1215, preventing ion congestion or vacancy caused by abrupt changes in transport rates between adjacent regions.

[0154] The polygonal micropores 122 in the fifth perforation zone 1215 have the smallest hole depth H5 and the smallest total capacity of polygonal micropores 122 in the region. While meeting the requirements of low current density ion transport, the ineffective depth of polygonal micropores 122 in the active material layer 120 is minimized, and the polygonal micropores 122 are prevented from being too deep and damaging the structural integrity of the active material layer 120.

[0155] For the high-silicon system electrochemical devices mentioned above (including but not limited to these), the following approach can be used when drilling holes on the electrode surface:

[0156] In some implementations, refer to Figure 13 H3, H4, and H5 satisfy the condition: H3 = H4 = H5.

[0157] This embodiment is a customized design for a high-silicon electrochemical device. The core feature is that the third, fourth, and fifth drilling regions 1215 employ equal-depth drilling, while only the polygonal micropores 122 in the first and second drilling regions 1212 maintain a gradient in depth. The arrangement order of the drilling regions can be found in the aforementioned embodiment. The third, fourth, and fifth drilling regions 1215 cover the tab and the high-risk lithium plating area on one side.

[0158] Due to the tab current collection effect and concentrated winding pressure in the inner layer (third-fifth perforated areas 1215), and the slow lithium-ion diffusion of the high-silicon material, a continuously large-depth ion transport channel is required. The design of H3=H4=H5 ensures that the inner layer region maintains a large-depth ion transport channel, effectively improving ion diffusion efficiency and reducing lithium plating.

[0159] In some implementations, H1, H2, H3, H4, and H5 also satisfy the following conditions: 10μm≤H1≤14μm, 12μm≤H2≤16μm, 14μm≤H3≤20μm, 10μm≤H4≤20μm, and 10μm≤H5≤20μm.

[0160] For example, the depth H1 of the polygonal micro-hole 122 in the first perforated area 1211 can be 10μm, 11μm, 12μm, 13μm or 14μm, or within the range of any two of the above values.

[0161] The depth H2 of the polygonal micro-hole 122 in the second perforation area 1212 can be 12μm, 14μm or 16μm, or within the range of any two of the above values.

[0162] The depth H3 of the polygonal micro-hole 122 in the third perforation area 1213 can be 14μm, 16μm, 18μm or 20μm, or within the range of any two of the above values.

[0163] The depth H4 of the polygonal micro-hole 122 in the fourth perforation area 1214 can be 10μm, 12μm, 14μm, 15μm, 16μm, 18μm or 20μm, or within the range of any two of the above values.

[0164] The depth H5 of the polygonal micro-hole 122 in the fifth perforation area 1215 can be 10μm, 12μm, 14μm, 15μm, 16μm, 18μm or 20μm, or within the range of any two of the above values.

[0165] As long as the basic condition of H1 < H2 < H3 ≥ H4 ≥ H is met, the values ​​of H1, H2, H3, H4 and H5 can be selected within the ranges defined above.

[0166] In some implementations, refer to Figure 3 In the length direction of the first electrode 100, the distance between the edge of the second perforated area 1212 and the groove 120C is C1, where C1 satisfies: C1 ≥ 6 mm; and / or,

[0167] In the length direction of the first electrode 100, the distance between the fourth perforated area 1214 and the edge of the groove 120C is C2, and C2 satisfies: C2≥6mm.

[0168] Along the length direction of the first electrode 100 after it is unfolded (in the non-wound state), the groove 120C is formed in the active material layer 120 of the third perforated area 1213 (inner ring electrode position). The edge of the groove 120C near the second perforated area 1212 is defined as the outer ring edge of the groove 120C (corresponding to the winding end side); the edge of the second perforated area 1212 near the third perforated area 1213 is defined as the inner ring edge of the second perforated area 1212. The straight distance between the two is C1 (the length distance in the unfolded state, the arc distance after it is not wound).

[0169] Optionally, C1 needs to satisfy C1≥6mm, preferably 6mm~12mm, so that the third perforation area 1213 can cover the high current area around the groove 120C, and ensure that the second perforation area 1212 and the high current area around the groove 120C are safely isolated.

[0170] Along the length direction of the first electrode 100 after it is unfolded (in the non-winding state), the groove 120C is formed in the active material layer 120 of the third perforated area 1213 (inner ring electrode position). The edge of the groove 120C near the fourth perforated area 1214 is defined as the inner ring edge of the groove 120C (corresponding to the starting end side of the winding). The edge of the fourth perforated area 1214 near the third perforated area 1213 is defined as the outer ring edge of the fourth perforated area 1214. The straight distance between the two is C2 (the length distance in the unfolded state, the arc distance after winding).

[0171] Optionally, C2 needs to satisfy C2≥6mm, preferably 6mm~12mm, so that the third perforation area 1213 can cover the high current area around the groove 120C, and ensure that the fourth perforation area 1214 is safely isolated from the high current area around the groove 120C.

[0172] In some embodiments, one end of the first electrode 100 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 after winding.

[0173] The fifth punching area 1215, the fourth punching area 1214, the third punching area 1213, the second punching area 1212 and the first punching area 1211 are distributed sequentially from the winding start end to the winding end end.

[0174] In this embodiment, the distribution of the perforated areas is deeply coupled with the winding direction of the electrode sheet. One end of the first electrode sheet 100 is the winding start end (located in the inner circle of the electrode assembly after winding, closest to the center of the core), and the other end is the winding end end (located in the outer circle of the electrode assembly after winding, furthest from the center of the core). Along the winding direction (from the inner circle to the outer circle), the perforated areas are sequentially the fifth perforated area 1215 → the fourth perforated area 1214 → the third perforated area 1213 → the second perforated area 1212 → the first perforated area 1211, forming a distribution of high-density micropores in the inner circle (fifth-third) and sparse micropores in the outer circle (second-first), which precisely adapts to the pressure and current gradient of the wound cell structure such as the high-silicon anode system.

[0175] In some embodiments, the size and spacing of the multiple polygonal micropores 122 are equal. To ensure the uniformity of the ion transport channels within the perforated area, it can be set that the diameter, depth, and spacing of the multiple polygonal micropores 122 within the perforated area are equal, that is, the diameter, depth, and spacing of the multiple polygonal micropores 122 are equal.

[0176] In some embodiments, the spacing between the plurality of polygonal micropores 122 is L, where L satisfies: 2D≤L≤3D; and / or,

[0177] The ratio of the depth of the polygonal micropore 122 to the thickness of the active material layer 120 is A, where A satisfies: 0.5≤A≤0.7.

[0178] For example, the aperture spacing L of the plurality of polygonal micro-holes 122 can be 2D, 2.2D, 2.4D, 2.5D, 2.6D, 2.8D, or 3D, or fall within the range of any two of the above values, and can be set according to actual conditions. For example, if the aperture D of the polygonal micro-hole 122 is 25μm, then the aperture spacing L can range from 50μm to 75μm. By constraining the ratio range between the aperture spacing and aperture of the polygonal micro-hole 122 through 2D≤L≤3D, the coordinated setting of the aperture spacing and aperture of the polygonal micro-hole 122 is achieved.

[0179] Optionally, the ratio A of the pore depth of the polygonal micropore 122 to the thickness of the active material layer 120 can be 0.5, 0.6, or 0.7, or fall within any two of the above values, and can be set according to actual needs. For example, if the thickness of the active material layer 120 is 25 μm and the pore depth of the polygonal micropore 122 is 16 μm, the ratio A of the pore depth of the polygonal micropore 122 to the thickness of the active material layer 120 is 0.64. By using 0.5 ≤ A ≤ 0.7 to constrain the ratio range between the pore depth of the polygonal micropore 122 and the thickness of the active material layer 120, the pore depth of the polygonal micropore 122 relative to the thickness of the active material layer 120 is kept within a moderate range, avoiding the polygonal micropore 122 being too shallow or too deep.

[0180] In some implementations, refer to Figure 2 Along the length of the first electrode 100, a first distance E1 exists between one edge of the active material layer 120 and its nearest polygonal micropore 122, and a second distance E2 exists between the other edge of the active material layer 120 and its nearest polygonal micropore 122. E1 and E2 satisfy: 0 ≤ E1 ≤ 12 mm, 0 ≤ E2 ≤ 12 mm; and / or,

[0181] In the width direction of the first electrode 100, there is a third spacing E3 between one side edge of the active material layer 120 and the nearest polygonal micropore 122, and a fourth spacing E4 between the other side edge of the active material layer 120 and the nearest polygonal micropore 122. E3 and E4 satisfy: 0≤E3≤3mm, 0≤E4≤3mm.

[0182] Along the length of the first electrode 100 (parallel to the distribution direction of the scribed area), the active material layer 120 has two end edges. The edge near the starting end of the winding is defined as the starting edge of the active material layer 120, and the edge near the ending end of the winding is defined as the ending edge of the active material layer 120. E1 is the straight-line distance between the ending edge of the active material layer 120 and the adjacent polygonal micropore 122. E2 is the straight-line distance between the starting edge of the active material layer 120 and the adjacent polygonal micropore 122.

[0183] Optionally, E1 and E2 must satisfy 0≤E1≤12mm and 0≤E2≤12mm. For example, E1 and E2 can be 3mm, 6mm, 9mm, or 12mm, or fall within the range of any two of the above values. That is, the polygonal micropores 122 at the corresponding edges of the active material layer 120 (winding end), starting edge (winding start), and perforation area maintain a spacing of E1 and E2, leaving blank areas without perforation, and retaining only the complete active material layer 120.

[0184] Along the width direction of the first electrode 100 (perpendicular to the distribution direction of the scribed area), the active material layer 120 has two side edges, one of which 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. E3 is the straight-line distance between the first side edge of the active material layer 120 and its adjacent polygonal micropore 122; E4 is the straight-line distance between the second side edge of the active material layer 120 and its adjacent polygonal micropore 122.

[0185] Optionally, E3 and E4 must satisfy 0≤E3≤3mm and 0≤E4≤3mm. For example, E3 and E4 can be 1mm, 2mm, or 3mm, or fall within the range of any two of the above values. That is, the polygonal micropores 122 on the top and bottom edges of the active material layer 120 and the corresponding edges of the perforated area maintain a spacing of E3 and E4, respectively. The spaced areas are left blank without perforation, and only the complete active material layer 120 is retained.

[0186] This application also proposes an electronic device comprising the electrochemical device described in the foregoing embodiments. The specific structure of the electrochemical device is as described in the above embodiments. Since this electronic device adopts all the technical solutions of all the above embodiments, it at least has all the technical effects brought about by the technical solutions of the above embodiments, which will not be repeated here. The electronic device of this application can be any electronic device known in the prior art, such as mobile phones, laptops, tablets, wearable devices, gaming devices, home appliances, etc.

[0187] 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, 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. The first electrode includes a current collector and an active material layer disposed on the current collector. The active material layer has a perforated area along the length direction of the first electrode. The perforated area has a plurality of spaced polygonal micropores. The diameter of the polygonal micropores is D, and D satisfies: 3μm≤D≤50μm.

2. The electrochemical device according to claim 1, characterized in that, The number of perforated areas is multiple, and the multiple perforated areas are distributed sequentially along the length direction of the first electrode sheet; The active material layer is provided with a groove for exposing a portion of the surface of the current collector to connect to the tab. The plurality of perforated areas include a third perforated area that covers the groove, and the diameter of the polygonal micropores in the third perforated area is not equal to the diameter of the polygonal micropores in at least a portion of the other perforated areas.

3. The electrochemical device according to claim 2, characterized in that, The plurality of perforated areas also includes a first perforated area and a second perforated area, wherein the first perforated area, the second perforated area and the third perforated area are distributed sequentially along the length direction of the first electrode sheet; The diameter of the polygonal micro-hole in the first punching area is D1 and the spacing between the holes is L1. The diameter of the polygonal micro-hole in the second punching area is D2 and the spacing between the holes is L2. The diameter of the polygonal micro-hole in the third punching area is D3 and the spacing between the holes is L3. D1, D2, and D3 satisfy: D1 < D2 < D3, and L1, L2, and L3 satisfy: L1 = L2 = L3.

4. The electrochemical device according to claim 3, characterized in that, The perforation area further includes a fourth perforation area and a fifth perforation area, and the first perforation area, the second perforation area, the third perforation area, the fourth perforation area and the fifth perforation area are distributed sequentially along the length direction of the first electrode sheet; The diameter of the polygonal micro-hole in the fourth punching area is D4 and the spacing between the holes is L4. The diameter of the polygonal micro-hole in the fifth punching area is D5 and the spacing between the holes is L5. D3, D4, and D5 satisfy: D3≥D4≥D5, and L3, L4, and L5 satisfy: L3=L4=L5.

5. The electrochemical device according to claim 4, characterized in that, The conditions D3, D4, and D5 satisfy: D3 = D4 = D5.

6. The electrochemical device according to claim 2, characterized in that, The plurality of perforated areas also includes a first perforated area and a second perforated area, wherein the first perforated area, the second perforated area and the third perforated area are distributed sequentially along the length direction of the first electrode sheet; The diameter of the polygonal micro-hole in the first punching area is D1 and the spacing between the holes is L1. The diameter of the polygonal micro-hole in the second punching area is D2 and the spacing between the holes is L2. The diameter of the polygonal micro-hole in the third punching area is D3 and the spacing between the holes is L3. D1, D2, and D3 satisfy: D1>D2>D3, and L1, L2, and L3 satisfy: L1>L2>L3.

7. The electrochemical device according to claim 6, characterized in that, The plurality of perforated areas also includes a fourth perforated area and a fifth perforated area, and the first perforated area, the second perforated area, the third perforated area, the fourth perforated area and the fifth perforated area are distributed sequentially along the length direction of the first electrode sheet; The diameter of the polygonal micro-holes in the fourth punching area is D4 and the spacing between the holes is L4. The diameter of the polygonal micro-holes in the fifth punching area is D5 and the spacing between the holes is L5. D3, D4, and D5 satisfy: D3 ≤ D4 ≤ D5, and L3, L4, and L5 satisfy: L3 <L4<L5。 8. The electrochemical device according to claim 7, characterized in that, The conditions D3, D4, and D5 satisfy: D3 = D4 = D5.

9. The electrochemical device according to claim 4 or 7, characterized in that, The depth of the polygonal micro-hole in the first punching area is H1, the depth of the polygonal micro-hole in the second punching area is H2, the depth of the polygonal micro-hole in the third punching area is H3, the depth of the polygonal micro-hole in the fourth punching area is H4, and the depth of the polygonal micro-hole in the fifth punching area is H5. H1, H2, H3, H4, and H5 satisfy: H1 < H2 < H3, and H3 ≥ H4 ≥ H5.

10. The electrochemical device according to claim 9, characterized in that, H3, H4, and H5 satisfy the following condition: H3 = H4 = H5.

11. The electrochemical device according to claim 5 or 8, characterized in that, Along the length of the first electrode, the distance between the second perforated area and the edge of the groove is C1, wherein C1 satisfies: C1 ≥ 6 mm; and / or, Along the length of the first electrode, the distance between the fourth perforated area and the edge of the groove is C2, where C2 satisfies: C2≥6mm.

12. The electrochemical device according to claim 5 or 8, characterized in that, One end of the first electrode is the starting end of the winding located in the inner ring of the electrode assembly after winding, and the other end is the ending end of the winding located in the outer ring of the electrode assembly after winding. The fifth, fourth, third, second, and first punching areas are distributed sequentially from the winding start end toward the winding finish end.

13. The electrochemical device according to claim 1, characterized in that, The size and spacing of the multiple polygonal micropores are all equal.

14. The electrochemical device according to claim 13, characterized in that, The spacing between the plurality of polygonal micropores is L, wherein L satisfies: 2D≤L≤3D; and / or, The ratio of the depth of the polygonal micropores to the thickness of the active material layer is A, where A satisfies: 0.5 ≤ A ≤ 0.

7.

15. The electrochemical device according to claim 1, characterized in that, Along the length of the first electrode, a first distance E1 exists between one edge of the active material layer and the nearest polygonal micropore therein, and a second distance E2 exists between the other edge of the active material layer and the nearest polygonal micropore therein, wherein E1 and E2 satisfy: 0 ≤ E1 ≤ 12 mm, 0 ≤ E2 ≤ 12 mm; and / or, In the width direction of the first electrode, there is a third spacing E3 between one edge of the active material layer and the nearest polygonal micropore there is a fourth spacing E4 between the other edge of the active material layer and the nearest polygonal micropore there is, wherein E3 and E4 satisfy: 0≤E3≤3mm, 0≤E4≤3mm.

16. An electronic device, characterized in that, Includes the electrochemical device as described in any one of claims 1 to 15.

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