Electrochemical device and electronic equipment

Abstract

The utility model discloses an electrochemical device and electronic equipment, electrochemical device includes electrode subassembly, and electrode subassembly includes mutually laminated coiling setting's first pole piece, diaphragm and second pole piece, and the polarity of second pole piece is opposite with first pole piece, and first pole piece has the multiple straight area and multiple corner area of alternately arranged along its coiling direction, and first pole piece includes current collector and sets up the active material layer of current collector at least one side surface, and the active material layer of current collector at least one side surface sets up the scribed line area at at least partial corner area, and scribed line area is provided with multiple polygonal line frames that are arranged in grid, and polygonal line frame is formed by the concave groove that communicates in order and surrounds. The utility model discloses an electrochemical device in the corner of pole piece adopts multiple polygonal line frames that are arranged in grid, and polygonal line frame is formed by the concave groove that communicates in order and surrounds, thereby forms multidimensional solid ion transmission network, makes ion can diffuse from multiple directions, expands ion diffusion area, and improves ion diffusion efficiency.

Description

Technical Field

[0001] This utility model 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, to effectively improve electrolyte wetting, the industry commonly uses laser drilling technology to process straight groove structures along the longitudinal direction (i.e., the width direction of the electrode) on the surface of the corner area of ​​the cathode electrode to facilitate ion transport. However, the ion transport channels constructed by the straight grooves have a small ion diffusion area and low diffusion efficiency. Utility Model Content

[0005] The main objective of this invention is to propose an electrochemical device that addresses the technical problem of small ion diffusion area and low diffusion efficiency in existing lithium batteries, where straight grooves are used to construct ion transport channels in the corner areas of the cathode electrode.

[0006] To achieve the above objectives, this utility model proposes an electrochemical device, which includes an electrode assembly. The electrode assembly includes a first electrode, a diaphragm, and a second electrode that are stacked and wound around each other, 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 a scribing area disposed at at least part of the corner region.

[0008] The marked area is provided with multiple polygonal frames arranged in a grid pattern, and the polygonal frames are formed by sequentially connected grooves.

[0009] Optionally, the multiple polygonal wireframes may have the same size.

[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 scribing 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 length of the groove in the plurality of scribed 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 length of the groove in the plurality of scribed areas between the receiving groove and the winding end end gradually increases.

[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 groove width and groove depth of the grooves in the plurality of scribed 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 groove width and groove depth of the grooves in the plurality of scribed areas between the receiving groove and the winding end end gradually decrease.

[0015] 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.

[0016] The accommodating groove is provided with the marking area at the K1 consecutive corner areas on the side facing the winding start end, and the accommodating groove is provided with the marking area at the K2 consecutive corner areas on the other side facing the winding end end.

[0017] 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).

[0018] Optionally, the length of the groove is A, wherein A satisfies: 50μm≤A≤200μm; and / or,

[0019] The groove width is X, where X satisfies: 20μm ≤ X ≤ 80μm; and / or,

[0020] The thickness of the active material layer is S, and the groove depth is H, wherein H satisfies: 0.3S≤H≤0.7S, and / or, S satisfies: 20μm≤S≤200μm.

[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 polygonal frame closest to it, and a second spacing E2 between the other edge of the active material layer and the polygonal frame closest to it, wherein E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

[0022] Optionally, the groove is formed by a plurality of continuously arranged and interconnected micropores, the projection of which onto the thickness of the active material layer is circular, elliptical, fan-shaped or polygonal.

[0023] Optionally, the pore size of the micropore is D, wherein D satisfies: 5μm≤D≤20μm.

[0024] This invention also proposes an electronic device comprising the electrochemical apparatus described above.

[0025] In the electrochemical device of this invention, 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 a scribing area at at least part of the corner region. The scribing area has multiple polygonal frames arranged in a grid pattern. The polygonal frames are formed by sequentially connected grooves. The groove enclosure structure of the polygonal frames and the grid arrangement and connection structure of the multiple polygonal frames form a multi-dimensional three-dimensional ion transport network at the corner position of the electrode, which allows ions to diffuse from multiple directions, expands the ion diffusion area, and improves the ion diffusion efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the electrode assembly of an electrochemical device in one embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the first electrode plate of the electrode assembly in one embodiment of the present invention from a certain perspective;

[0028] Figure 3 This is a schematic diagram of the structure of the first electrode plate of the electrode assembly in one embodiment of the present invention from another perspective;

[0029] Figure 4 This is a schematic diagram of the structure of the first electrode plate of the electrode assembly in another embodiment of the present invention;

[0030] Figure 5 for Figure 4 A schematic diagram of a portion of the active material layer of the first electrode in the embodiment;

[0031] Figure 6 for Figure 4 A schematic diagram of another part of the active material layer of the first electrode in the embodiment;

[0032] Figure 7 This is a schematic diagram of the polygonal wireframe structure in one embodiment of the present invention;

[0033] Explanation of icon numbers:

[0034] 100 First Pole Film 200 diaphragm 300 Second pole plate 100P Straight area 100G Corner area 110 current collector 120 active material layer 121 lined area 122 Polygonal wireframe 1221 groove 120C Container slot 1221K micropores

[0035] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0037] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment 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.

[0038] 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.

[0039] Furthermore, the use of terms such as "first" and "second" in this utility model 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 by this utility model.

[0040] This utility model provides 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.

[0041] 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 scribing region 121 disposed at at least part of the corner region 100G.

[0042] The marking area 121 is provided with a plurality of polygonal wire frames 122 arranged in a grid pattern, and the polygonal wire frames 122 are formed by sequentially connected grooves 1221.

[0043] 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.

[0044] 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.

[0045] 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). The straight regions 100P are approximately planar regions after winding, and the corner regions 100G are arc-shaped regions after winding.

[0046] 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 surface of the current collector 110, preferably both surfaces, to improve energy density. Its composition includes active material, conductive agent (such as carbon black, graphene), and binder (such as polyvinylidene fluoride PVDF).

[0047] The active material layer 120 on at least one side surface of the current collector 110 has scribe lines 121 at at least some corner areas 100G (preferably all corner areas 100G). The scribe lines 121 are used to construct ion transport channels. The scribe lines 121 are provided with a plurality of polygonal frames 122 arranged in a grid pattern, and adjacent polygonal frames 122 are connected by sharing edges to form a continuous ion transport network. The shape of the polygonal frames 122 is selected from at least one of regular hexagons, squares, or equilateral triangles, with regular hexagons being the most preferred because regular hexagons have the best close packing properties, which can maximize the filling of the scribe lines 121 and reduce blank areas. The polygonal frames 122 are enclosed by sequentially connected grooves 1221. The grooves 1221 are scribes on the surface of the active material layer 120, which do not penetrate the current collector 110, and the grooves 1221 of the same polygonal frame 122 are interconnected to form a closed "frame channel".

[0048] The core advantage of this electrochemical device stems from the multi-dimensional ion transport network constructed by the grid-like polygonal wireframe 122 in the 100G scribe line area 121 at the electrode corner region. Its working process is as follows:

[0049] Electrolyte wetting stage:

[0050] After the electrochemical device is assembled and injected with electrolyte, at the corner region 100G of the first electrode 100, the electrolyte rapidly diffuses along the groove 1221 of the scribed region 121. Since the grooves 1221 of the polygonal frame 122 are interconnected (e.g., the 6 sides of a regular hexagon are connected to 6 adjacent regular hexagons respectively), the electrolyte can form a "three-dimensional wetting network" in the corner region 100G.

[0051] Ion transport stage (charge and discharge process):

[0052] During discharge, ions in the second electrode 300 (anode) are deintercalated and migrate with the electrolyte to the corner region 100G of the first electrode 100 (cathode). At this time, ions can diffuse in multiple directions through the grooves 1221 of the scribe line region 121 (e.g., within a regular hexagonal frame, ions can diffuse along the six grooves 1221 to adjacent frames), increasing the diffusion paths and the diffusion area.

[0053] During charging, ions are de-embedded from the active material layer 120 of the first electrode 100 and rapidly transported to the anode along the same grid-like grooves 1221, avoiding ion congestion in the corner area 100G and ensuring a stable ion transport rate during charging and discharging.

[0054] Furthermore, the constructed multidimensional ion transport network enables rapid heat dissipation, preventing localized heat accumulation and thus improving the performance of the electrochemical device. Additionally, during the winding process, the active material layer 120 in the corner region 100G is susceptible to tensile forces, while the grid-like polygonal wire frame 122 disperses stress, reducing active material shedding.

[0055] In the electrochemical device of this embodiment, the groove 1221 enclosure structure of the polygonal wire frame 122 and the grid arrangement and connection structure adopted by the multiple polygonal wire frames 122 form a multi-dimensional three-dimensional ion transport network at the corner position of the electrode, which allows ions to diffuse from multiple directions, expands the ion diffusion area, and improves the ion diffusion efficiency, which helps to improve the corner lithium plating.

[0056] In some embodiments, refer to Figure 2 and Figure 3 Multiple polygonal wireframes 122 are of the same size. In this embodiment, the polygonal wireframes 122 are of the same size, specifically in that the length, width, and depth of the groove 1221 are identical. That is, the length, width, and depth of the groove 1221 of multiple polygonal wireframes 122 are the same. Wireframes of uniform size can achieve shared edge connectivity, and adjacent wireframes share the groove 1221, with consistent groove width and depth, avoiding local misalignment or connectivity breaks in the groove 1221 due to differences in wireframe size, ensuring that the ion transport channel has no dead angles. Furthermore, based on this, the polygonal wireframes 122 can maintain the same size between different scribed areas 121.

[0057] In some embodiments, refer to Figure 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 scribing areas 121.

[0058] 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 scribing areas 121. That is, the receiving groove 120C is located at a straight area 100P, and the corner areas 100G on both sides of the straight area 100P are respectively provided with scribing areas 121, so that the receiving groove 120C is located between the two adjacent scribing areas 121.

[0059] 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 edge of the starting end of winding and the edge of the ending end of winding), 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. Its 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.

[0060] The receiving tank 120C is located between two adjacent scribing regions 121. When lithium ions migrate from the tabs to the scribing regions 121 on both sides, they can achieve rapid transport and diffusion through the multi-dimensional ion transport channels constructed by the scribing regions 121. Furthermore, the grooves 1221 of the polygonal frame 122 in the scribing region 121 can provide electrolyte storage space, accelerate the electrolyte wetting speed, increase the CB value at the corner region 100G, and improve corner lithium deposition.

[0061] In some embodiments, refer to Figure 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.

[0062] Along the direction from the receiving groove 120C to the winding start end, the length of the groove 1221 of the several scribed 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 length of the groove 1221 of the several scribed 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, the design of the grooves 1221 in the scribed areas 121 at at least some corner regions 100G is optimized. Along the winding direction of the first electrode 100, by adjusting the length A of the grooves 1221 in the scribed areas 121 at different corner regions 100G, the ion transport channel density is matched with the requirements for ion transport and electrolyte storage. The length of the groove 1221 refers to the effective length of a single groove 1221 constituting the polygonal frame 122 in its extending direction.

[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 endpoint), 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 endpoint); the receiving groove 120C is located between the winding start end and the winding end end, and ≥2 scribing areas 121 are distributed on both sides (e.g., 8 scribing areas 121 are set on the inner ring side and 8 scribing areas 121 are set on the outer ring side, for a total of 16 scribing areas 121 are 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 length of the groove 1221 of several scribing areas 121 on the path gradually increases; that is, the scribing area 121 closer to the receiving groove 120C (electrode tab) has the shortest groove 1221 length; the further away from the receiving groove 120C (that is, the closer to the starting end / ending end of the electrode winding) the scribing area 121 is, the longer the groove 1221 length.

[0065] The grooves 1221 on both sides of the receiving tank 120C closest to the scribed area 121 are the shortest in length and have 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 grooves 1221 on the edge scribed area 121 near the winding start / end end are the longest in length and have the lowest channel density. Their channel area accounts for a lower proportion, which not only meets the low ion transport and electrolyte storage requirements of the edge area, but also retains more active material and avoids 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, refer to Figure 5 and Figure 6Along 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.

[0068] Along the direction from the receiving groove 120C to the winding start end, the groove width and groove depth of the groove 1221 of the several scribed 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 groove width and groove depth of the groove 1221 of the several scribed areas 121 between the receiving groove 120C and the winding end end gradually decrease.

[0069] In this embodiment, considering the voltage drop and ion concentration gradient difference generated during current transmission in the current collector 110, the design of the groove 1221 in the scribed area 121 at at least a portion of the corner region 100G is optimized. Along the winding direction of the first electrode 100, by adjusting the groove width X and groove depth H of the groove 1221 in the scribed area 121 at different corner regions 100G, the ion transmission channel volume is matched with the requirements for ion transmission and electrolyte storage. Here, the groove width X of the groove 1221 refers to the lateral dimension at the opening of the groove 1221, and the groove depth H refers to the vertical distance from the opening of the groove 1221 to the bottom of the groove.

[0070] 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 endpoint), 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 endpoint); the receiving groove 120C is located between the winding start end and the winding end end, and ≥2 scribing areas 121 are distributed on both sides (e.g., 8 scribing areas 121 are set on the inner ring side and 8 scribing areas 121 are set on the outer ring side, for a total of 16 scribing areas 121 are 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 groove width and groove depth of the grooves 1221 in several scribed areas 121 on the path gradually decrease simultaneously; that is, the groove width and groove depth of the groove 1221 in the scribed area 121 close to the receiving groove 120C (electrode tab) are the widest and the deepest (the channel volume is the largest); the further away from the receiving groove 120C (that is, the closer to the winding start end / winding end end of the electrode) the scribed area 121 is, the narrower the groove width and the shallower the groove depth (the channel volume gradually decreases).

[0071] The grooves 1221 on the sides of the scribbled area 121 closest to the receiving tank 120C have the largest groove width and depth, and the largest channel volume. Their large ion transport channel volume can quickly conduct ions generated near the tab due to high current density and store more electrolyte. The grooves 1221 on the edge scribbled area 121 near the winding start / end end have the smallest groove width and depth, and the smallest channel volume. The reduced channel volume meets 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.

[0072] 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.

[0073] In some embodiments, refer to Figure 2 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 marking area 121 is provided at the K1 consecutive corner areas 100G on the side of the receiving groove 120C facing the winding start end, and a marking area 121 is provided at the K2 consecutive corner areas 100G 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 scribing 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 counted 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 set scribing areas 121 on the side of the receiving groove 120C facing the winding start end; K2 is the number of corner areas 100G of the continuously set scribing 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 at least one scribing area 121 on both sides of the receiving groove 120C achieves 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 marking 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 marking 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), and 1 ≤ K2 ≤ 0.5 * (N-1). Taking N = 21 as an example, 1 ≤ K1 ≤ 10, and 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 marking 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 marking 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, the length of the groove 1221 is A, where A satisfies: 50μm ≤ A ≤ 200μm; and / or,

[0082] The groove width of groove 1221 is X, where X satisfies: 20μm≤X≤80μm; and / or,

[0083] The thickness of the active material layer 120 is S, and the groove depth of the groove 1221 is H, where H satisfies: 0.3S≤H≤0.7S, and / or S satisfies: 20μm≤S≤200μm.

[0084] For example, the length A of the groove 1221 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, or 150μm, or fall within the range of any two of the above values. By limiting the value range of the groove 1221 length A to 50μm to 200μm, the length of the groove 1221 is kept moderate. This avoids the active material from easily falling off due to the groove 1221 being too short, while also preventing excessive loss of active material due to the groove 1221 being too long, thus ensuring the cell capacity.

[0085] For example, the groove width X of the groove 1221 can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, or 80μm, or fall within the range of any two of the above values. By limiting the groove width X of the groove 1221 to a range of 20μm to 80μm, the groove width of the groove 1221 is kept moderate, which can avoid the increase in ion transport resistance caused by the groove width being too narrow, and also prevent the decrease in the mechanical strength of the electrode caused by the groove width being too wide.

[0086] 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 groove depth H of the groove 1221 can be 0.3S, 0.4S, 0.5S, 0.6S, or 0.7S, or fall within any two of the above values. By limiting the groove depth H of the groove 1221 to a range of 0.3S to 0.7S, the groove depth of the groove 1221 is kept moderate, avoiding both insufficient liquid storage space due to excessively shallow groove depth and decreased mechanical strength of the electrode due to excessively deep groove depth. 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.

[0087] In some embodiments, refer to Figure 2 In the width direction of the first electrode 100, there is a first gap E1 between one side edge of the active material layer 120 and the polygonal frame 122 that is closest to it, and there is a second gap E2 between the other side edge of the active material layer 120 and the polygonal frame 122 that is closest to it. E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

[0088] Along the width direction of the first electrode 100 (perpendicular to the distribution direction of the scribed 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.

[0089] E1 is the straight-line distance between the first side edge of the active material layer 120 and the polygonal frame 122 of the corresponding side edge of the scribing area 121 (one side of the scribing 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 polygonal frame 122 of the corresponding side edge of the scribing area 121 (the other side of the scribing area 121 along the width direction of the electrode).

[0090] 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.

[0091] In some embodiments, refer to Figure 7 The groove 1221 is formed by a plurality of continuously arranged and interconnected micropores 1221K. The projection of the micropores 1221K in the thickness direction of the active material layer 120 is circular, elliptical, fan-shaped or polygonal.

[0092] To further improve the ion transport efficiency and structural anti-expansion toughness of the groove 1221, the groove 1221 is formed by multiple continuously arranged and interconnected micropores 1221K (the micropores 1221K are arranged sequentially along the length of the groove 1221, with adjacent micropores 1221K partially overlapping or directly connected to form a continuous microchannel). Traditional grooves 1221 are only single macroscopic channels, with ion transport relying on diffusion from the inner wall of the groove 1221 to the active material layer 120. The micropores 1221K form a secondary channel; the macroscopic groove 1221 guides long-distance ion transport, while the microscopic micropores 1221K further shorten the diffusion path, improving ion diffusion efficiency. The projection of the micropores 1221K onto the thickness direction of the active material layer 120 can be circular, elliptical, fan-shaped, or polygonal. Polygons can be triangular, rectangular, hexagonal, etc., and this embodiment does not impose any limitations on this.

[0093] In some embodiments, the pore size of the micropore 1221K is D, where D satisfies: 5μm ≤ D ≤ 20μm. Exemplarily, the pore size D of the micropore 1221K can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, or 20μm, or fall within the range of any two of the aforementioned values.

[0094] This utility model embodiment also proposes an electronic device, which 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.

[0095] 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.

[0096] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. An electrochemical device, characterized in that, The electrode assembly includes a first electrode, a diaphragm, and a second electrode that are stacked and wound around each other, wherein the polarity of the second electrode is opposite to that of the first electrode. 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 a scribing area disposed at at least part of the corner region. The marked area is provided with multiple polygonal frames arranged in a grid pattern, and the polygonal frames are formed by sequentially connected grooves.

2. The electrochemical device according to claim 1, characterized in that, The multiple polygonal wireframes are all the same size.

3. The electrochemical device according to claim 1, characterized in that, The active material layer on at least one side surface of the current collector is provided with a receiving groove, which is used to expose a portion of the surface of the current collector, and the receiving groove is located between any two adjacent scribing areas.

4. The electrochemical device according to claim 3, characterized in that, 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. Along the direction from the receiving groove to the winding start end, the length of the groove in the plurality of scribed 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 length of the groove in the plurality of scribed areas between the receiving groove and the winding end end gradually increases.

5. The electrochemical device according to claim 3, characterized in that, 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. Along the direction from the receiving groove to the winding start end, the groove width and groove depth of the grooves in the plurality of scribed 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 groove width and groove depth of the grooves in the plurality of scribed areas between the receiving groove and the winding end end gradually decrease.

6. The electrochemical device according to claim 3, characterized in that, 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. The accommodating groove is provided with the marking area at the K1 consecutive corner areas on the side facing the winding start end, and the accommodating groove is provided with the marking area at the K2 consecutive corner areas on the other side facing the winding end end. 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).

7. The electrochemical device according to any one of claims 1 to 6, characterized in that, The length of the groove is A, and A satisfies: 50μm≤A≤200μm; and / or, The groove width is X, where X satisfies: 20μm≤X≤80μm; and / or, The thickness of the active material layer is S, and the groove depth is H, wherein H satisfies: 0.3S≤H≤0.7S, and / or, S satisfies: 20μm≤S≤200μm.

8. The electrochemical device according to any one of claims 1 to 6, characterized in that, In the width direction of the first electrode, there is a first spacing E1 between one edge of the active material layer and the polygonal frame closest to it, and there is a second spacing E2 between the other edge of the active material layer and the polygonal frame closest to it. E1 and E2 satisfy: 0≤E1≤3mm, 0≤E2≤3mm.

9. The electrochemical device according to any one of claims 1 to 6, characterized in that, The groove is formed by a plurality of continuously arranged and interconnected micropores, the projection of which onto the thickness of the active material layer is circular, elliptical, fan-shaped or polygonal.

10. The electrochemical device according to claim 9, characterized in that, The pore size of the micropore is D, and D satisfies: 5μm≤D≤20μm.

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

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