Roll core structure, electrochemical device comprising roll core structure and electronic equipment comprising roll core structure

Abstract

The invention relates to the technical field of electrochemical energy storage, and particularly discloses a roll core structure, which comprises a laminated structure obtained by sequentially laminating an anode pole piece, a diaphragm and a cathode pole piece, the laminated structure is wound around an elliptical track to form a roll core structure; one end, close to the elliptical track, of the anode plate is provided with a first winding starting end, and one end, close to the elliptical track, of the cathode plate is provided with a second winding starting end; an included angle theta formed by the first winding starting end and the second winding starting end relative to the center of the elliptical orbit is greater than or equal to 90 degrees and less than 180 degrees. The invention also discloses an electrochemical device and electronic equipment. By limiting the angles of the winding starting ends of the anode pole piece and the cathode pole piece relative to the center of the elliptical track and the winding track, the transverse deviation of the pole pieces in the winding process can be reduced, and the alignment degree of the pole pieces is remarkably improved; and the angle range can avoid local stretching at the bending part of the pole piece, reduce diaphragm wrinkles and active substance falling off, and reduce failure rate of the battery cell after circulation.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202511346806.0, filed on September 19, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of electrochemical energy storage technology, and in particular to a core structure and an electrochemical device and electronic device including the same. Background Technology

[0004] As electronic devices become smaller and lighter, it is expected that electrochemical devices used in these devices can maintain high energy density while being miniaturized and lightweight, thus meeting the requirements for long battery life of electronic devices.

[0005] Therefore, as the demand for high capacity and long range of cylindrical lithium-ion batteries continues to increase, the anode is gradually shifting from low silicon to high silicon. The volume expansion of high silicon anodes during charging and discharging is becoming more and more significant, which leads to deformation of the steel shell and expansion of the inner ring of the core, squeezing the separator and causing internal short circuits, which greatly affects the cycle life and safety of the battery.

[0006] Application content

[0007] The technical problem to be solved by this application is: how to solve the problem of deformation of the inner ring of the winding core and short circuit of the battery cell caused by the volume expansion of the high silicon anode.

[0008] To address the aforementioned technical problems, this application proposes a core structure comprising an anode sheet, a diaphragm, and a stacked structure formed by sequentially stacking them.

[0009] The stacked structure is wound around an elliptical trajectory to form the core structure;

[0010] The anode electrode has a first winding start end at the end near the elliptical trajectory, and the cathode electrode has a second winding start end at the end near the elliptical trajectory.

[0011] The angle between the first winding start end and the second winding start end relative to the center of the elliptical trajectory is θ, which satisfies: 90°≤θ<180°.

[0012] In some embodiments, the stacked structure has a first direction, a second direction, and a third direction that are perpendicular to each other, the stacked structure is wound in the second direction, and the major semi-axis of the elliptical trajectory is a and the minor semi-axis is b.

[0013] In the layer structure, the first winding starting end and the second winding starting end are spaced apart along the second direction by a distance Q; Q satisfies: Q≥1 / 2πb+a-b; and the cathode tab is projected along the third direction to fall within the anode tab.

[0014] In some embodiments, the elliptical trajectory has a major axis and a minor axis, the first winding starting end is located on the major axis, and the second winding starting end is located on the minor axis.

[0015] and / or,

[0016] the first winding starting end is located on the minor axis, and the second winding starting end is located on the major axis.

[0017] In some embodiments, in the layer structure, the anode tab comprises:

[0018] a current collector having a functional area and a blank area adjacent along the first direction;

[0019] an active material layer provided on at least one side of the current collector along the third direction, and the active material layer is coated on the functional area;

[0020] In some embodiments, in the layer structure, the active material layer is provided with a plurality of grooves extending along the first direction, and the plurality of grooves are spaced apart along the second direction.

[0021] In some embodiments, in the layer structure, along the third direction, the thickness of the active material layer is B, and the depth of the groove is H, and 0

[0022] In some embodiments, in the layer structure, along the second direction, the distance between two adjacent grooves is P, and 0

[0023] In some embodiments, in the layer structure, along the second direction, the width of the groove is W, and 0

[0024] In some embodiments, in the layer structure, along the first direction, the length of the active material layer is A, and the length of the groove is L, and 0

[0025] The application also provides an electrochemical device comprising the winding core structure.

[0026] The application also provides an electronic device comprising the electrochemical device.

[0027] The winding core structure, the electrochemical device and the electronic device provided by the application have the following beneficial effects compared with the prior art:

[0028] By limiting the angle of the winding starting end of the anode and cathode electrode pieces relative to the center of the elliptical trajectory and the elliptical winding trajectory, on the one hand, the lateral deviation of the electrode pieces during winding can be reduced, and the alignment of the electrode pieces can be significantly improved; on the other hand, the angle range can avoid local stretching at the bending part of the electrode pieces, reduce the folding of the diaphragm and the shedding of the active material, effectively solve the problem of deformation of the inner circle of the winding core and short circuit of the battery caused by the volume expansion of the high-silicon anode, reduce the failure rate of the battery after cycling, and improve the cycle life and safety of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0029] The embodiments in the present application will not be limited to the following description of the drawings, and the drawings described below are only part of the embodiments in the present application. Those skilled in the art can obtain other drawing part embodiments according to the content in the application.

[0030] Figure 1 is a front view of the anode electrode piece of the layer structure described in Embodiment 1 of the present application.

[0031] Figure 2 is a top view of the anode electrode piece of the layer structure described in Embodiment 1 of the present application.

[0032] Figure 3 is a schematic diagram of the elliptical trajectory described in Embodiment 1 of the present application.

[0033] Figure 4 is a schematic diagram of the layer structure described in Embodiment 1 of the present application.

[0034] Figure 5 is a simplified schematic diagram of the winding core structure described in Embodiment 1 of the present application.

[0035] Figure 6 is a schematic diagram of the winding core structure described in Embodiment 1 of the present application. Figure 5 is an enlarged schematic diagram of C in the present application.

[0036] Figure 7 is a schematic diagram when θ=90° in another embodiment of the present application.

[0037] Figure 8 is a schematic diagram when θ<90° in Embodiment 1 of the present application.

[0038] Figure 9 is a schematic diagram when 90°<θ<180° in Embodiment 1 of the present application.

[0039] REFERENCE NUMERALS:

[0040] 10, anode electrode piece; 101, first winding starting end; 11, current collector; 111, functional area; 112, empty foil area; 12, active material layer; 121, grooving;

[0041] 20, cathode tab; 201, second winding start end;

[0042] 30, separator;

[0043] 40, elliptical trajectory; 41, major axis; 42, minor axis;

[0044] X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0045] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application. The embodiments of the present application can omit unnecessary detailed descriptions. For example, there are cases of omitting detailed descriptions of well-known matters and repeated descriptions of actually identical structures. This is to avoid the following description from becoming unnecessarily lengthy, and to facilitate the understanding of those skilled in the art.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application; the terms "include" and "have" and any variations thereof used in the specification and claims of this application and the above description of the drawings are intended to cover the inclusion not the exclusion of one or more elements.

[0047] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0048] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like in the present application are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0049] The terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or a quantity of the specified technical features. Thus, a feature defined with "first", "second", etc. can include at least one of the feature. In the description of the application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise expressly specified and limited. Furthermore, "first", "second" and the like are not intended to describe corresponding components.

[0050] In addition, quantities, ratios, and other numerical values are sometimes presented in a range format. It is to be understood that such range format is used for convenience and brevity and should be construed as having been followed had each numerical value been explicitly recited. Therefore, measurement of parameters is understood to be open-ended unless otherwise indicated.

[0051] Furthermore, unless otherwise expressly specified and limited, the terms "install," "connect," "couple," "fixedly connected," "connected," "connected to," "coupled to," "coupled with," "connected with," "fixedly coupled," "directly coupled," "indirectly coupled," "connected internally," and the like, should not be construed as being limited to direct connections, as these terms can refer to either direct connections or indirect connections via intermediate medium unless otherwise expressly specified and limited by the context.

[0052] In the DETAILED DESCRIPTION and in the claims, a list of items joined by the term "one of" or "one of each" can mean any single one of the listed items. For example, if the items enumerated are A and B, then the phrase "one of A and B" means only A or, alternatively, only B. In another example, if the items enumerated are A, B, and C, then the phrase "one of A, B, and C" means only A; only B; or only C. Item A can include a single element or multiple elements. Item B can include a single element or multiple elements. Item C can include a single element or multiple elements.

[0053] In the DETAILED DESCRIPTION and in the claims, a list of items joined by the term "at least one of" can mean any combination of the listed items. For example, if the items enumerated are A and B, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if the items enumerated are A, B, and C, then the phrase "at least one of A, B, and C" means only A; only B; only G; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.

[0054] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0055] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0056] Example 1

[0057] like Figure 1 and Figure 2 As shown, this application proposes a core structure, including an anode electrode 10, a cathode electrode 20 and a diaphragm 30. The diaphragm 30 is disposed between the anode electrode 10 and the cathode electrode 20. The anode electrode 10, the diaphragm 30 and the cathode electrode 20 are stacked in sequence to form a stacked structure. The stacked structure is wound around an elliptical trajectory 40 to form a core structure.

[0058] In some embodiments, the laminated structure has a first direction X, a second direction Y and a third direction Z perpendicular to each other, and the winding of the laminated structure is performed in the second direction Y; specifically, in the laminated structure, the anode pole piece 10 includes a current collector 11 and an active material layer 12, the current collector 11 has a functional area 111 and a hollow foil area 112 adjacent along the first direction X; the active material layer 12 is arranged on at least one side of the current collector 11 along the third direction Z, and the active material layer 12 is coated on the functional area 111; wherein the active material layer 12 is provided with a plurality of grooves 121 extending along the first direction X, and the plurality of grooves 121 are arranged at intervals along the second direction Y; in this way, by arranging the grooves 121 on the active material layer 12, on the one hand, it is beneficial for the electrolyte to infiltrate the anode pole piece 10 through the grooves 121, increases the contact area of the electrolyte and the active material, shortens the diffusion path of lithium ions inside the anode pole piece, thereby improving the liquid phase conduction speed, relieving the polarization problem during high-rate charging, and improving the interface state; on the other hand, the arrangement of the grooves 121 can provide space for the expansion of the pole piece during the battery cycle process, which can not only reduce the deformation of the steel shell, but also avoid the expansion of the inner ring of the roll core extruding the separator, thereby improving the cycle life and safety of the battery.

[0059] In some embodiments, to avoid lithium precipitation, along the third direction Z, the thickness of the active material layer 12 is B, and the depth of the groove 121 is H, which satisfies: 0

[0060] In some embodiments, along the second direction Y, the distance between two adjacent grooves 121 is P, which satisfies: 0

[0061] In some embodiments, the width of the groove 121 along the second direction Y is W, satisfying: 0 < W ≤ 100 μm; this can shorten the solid-phase diffusion path (such as Li in a graphite anode). + This facilitates interlayer diffusion, alleviates polarization issues during high-rate charging, and improves fast-charging performance. Simultaneously, it reduces local current density, minimizing uneven lithium-ion deposition on the anode electrode 10 surface, thereby suppressing lithium dendrite growth. If W > 100 μm, the mechanical strength of the anode electrode 10 will decrease, and the active material will easily peel off from the current collector after long-term cycling, accelerating capacity decay. For example, the width W of the groove 121 can be 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm, or fall within the range of any two of the above values.

[0062] In some embodiments, along the first direction X, the length of the active material layer 12 is A, and the length of the groove 121 is L, satisfying: 0 < L ≤ A. This allows the microchannels formed by the groove 121 to directionally guide the electrolyte flow and shorten the wetting path. In addition, when L < A, stress concentration at the edge of the anode electrode 10 can be avoided, reducing the risk of cracking of the active material layer during rolling or slitting; when L = A, there is no need to adjust the coating die or slitting equipment, and it can be directly adapted to existing production lines to meet mass production requirements.

[0063] In some embodiments, this application uses an anode electrode 10 without grooves 121 and an anode electrode 10 with grooves 121 (groove depth H = 0.5B) to assemble a core structure with a cathode electrode 20, respectively, and tests the cycle performance to compare the thickness difference of the anode electrode 10 before and after cycling, as shown in Table 1 below:

[0064] Table 1. Comparison of Cyclic Performance Test Data for Grooved and Ungrooved Anodes

[0065]

[0066]

[0067] As shown in Table 1 above, the expansion thickness of the anode electrode 10 with groove 121 after 600 cycles is significantly reduced by about 3.5% compared to the expansion thickness of the anode electrode 10 without groove 121 after 600 cycles.

[0068] As can be seen, by setting multiple grooves 121 extending along the first direction X on the active material layer 12 of the anode electrode 10, and the multiple grooves 121 being spaced apart along the second direction Y, and limiting the thickness B of the active material layer 12 and the depth H of the grooves 121 to satisfy 0 < H ≤ 0.5B, on the one hand, it is beneficial for the electrolyte to wet the anode electrode through the grooves 121, increasing the contact area between the electrolyte and the active material, shortening the diffusion path of lithium ions inside the electrode, thereby improving the liquid phase conduction speed, alleviating the polarization problem during high-rate charging, and improving the interface state. Moreover, H ≤ 0.5B can reduce the uneven deposition of lithium ions on the anode surface, suppress the formation of lithium dendrites, and improve safety. On the other hand, the setting of the grooves 121 can reserve space for the expansion of the electrode during battery cycling, which can reduce the deformation of the steel shell and avoid the inner ring of the core from expanding and squeezing the separator, thereby improving the cycle life and safety of the battery.

[0069] In some implementations, such as Figure 3 and Figure 4 As shown, the anode electrode 10, cathode electrode 20, and separator 30 are wound around an elliptical trajectory 40. This greatly reduces the stress generated during expansion due to the large curvature of the inner ring of the core, disperses the expansion force, prevents electrode wrinkling or active material layer shedding and leakage, reduces the risk of short circuits, and improves the cycle life of the battery. Compared to a circular trajectory, the elliptical trajectory shows no significant deformation before and after cycling, and the cell exhibits no abnormalities during cycling. In contrast, the circular trajectory exhibits cycle failure, with a cycle failure rate reaching 16.70% according to tests, and the inner separator is at risk of puncture.

[0070] In some implementations, such as Figure 4 As shown, to prevent lithium ions at the edge of the cathode electrode from forming lithium dendrites due to excessively high local current density, which could then pierce the separator and cause a short circuit, the orthogonal projection of the cathode electrode 20 along the third direction Z falls into the anode electrode 10, thereby avoiding lithium deposition.

[0071] In some implementations, such as Figure 4As shown, the anode tab 10 has a first winding starting end 101 near one end of the elliptical trajectory 40, and the cathode tab 20 has a second winding starting end 201 near the other end of the elliptical trajectory 40; wherein the elliptical trajectory 40 has a long semi-axis a and a short semi-axis b, and the distance between the first winding starting end 101 and the second winding starting end 201 in the second direction Y in the stacked structure is Q; and Q satisfies: Q≥1 / 2πb+a-b; in this way, the curvature change of the elliptical trajectory 40 can reduce the local stress of the tab edge, and: the length of the anode tab 10 extending out of the cathode tab 20, i.e. Q, Q≥1 / 2πb+a-b, can further disperse the winding tension and reduce the risk of tab creases or breakage, and: the extension length matches the progressive winding path of the elliptical trajectory 40 to form a more uniform separator-tab gap, further improving the electrolyte infiltration speed.

[0072] In some embodiments, as shown in FIG. 1, the first winding starting end 101 and the second winding starting end 201 are located on the long axis 41 and the short axis 42 of the elliptical trajectory 40, respectively. Figure 5 As shown in the winding core structure, the included angle formed by the first winding starting end 101 and the second winding starting end 201 relative to the center of the elliptical trajectory 40 is θ, and 90°≤θ<180° is satisfied; and exemplarily, the included angle θ can be 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, or within the range between any two of the above values; using the winding entry angle in this range, on the one hand, the lateral deviation of the tab during winding can be reduced, and the tab alignment can be significantly improved; on the other hand, this angle range can avoid local stretching at the tab bending position, reduce separator creases (crease rate reduced from 5% to 0.1%) and active material shedding, and reduce the cycle failure rate of the battery. Through experiments, if θ<90° (such as θ=80°), the cycle failure rate is as high as 15.7%; if 90°<θ<180° (such as θ=120°), the cycle failure rate is reduced to 8.3%; and if θ=90°, the cycle failure rate is reduced to zero. The present application preferably uses θ=90° to avoid the failure phenomenon after battery cycling and improve the cycle life of the battery. Figure 8 Figure 9 Figure 5

[0073] In some embodiments, as shown in FIG. 1, the first winding starting end 101 and the second winding starting end 201 are located on the long axis 41 and the short axis 42 of the elliptical trajectory 40, respectively. Figure 3 As shown in the winding core structure, the included angle formed by the first winding starting end 101 and the second winding starting end 201 relative to the center of the elliptical trajectory 40 is θ, and 90°≤θ<180° is satisfied; and exemplarily, the included angle θ can be 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 179°, or within the range between any two of the above values; using the winding entry angle in this range, on the one hand, the lateral deviation of the tab during winding can be reduced, and the tab alignment can be significantly improved; on the other hand, this angle range can avoid local stretching at the tab bending position, reduce separator creases (crease rate reduced from 5% to 0.1%) and active material shedding, and reduce the cycle failure rate of the battery. Through experiments, if θ<90° (such as θ=80°), the cycle failure rate is as high as 15.7%; if 90°<θ<180° (such as θ=120°), the cycle failure rate is reduced to 8.3%; and if θ=90°, the cycle failure rate is reduced to zero. The present application preferably uses θ=90° to avoid the failure phenomenon after battery cycling and improve the cycle life of the battery. Figure 7 Figure 6

[0074] Example 2​​​​​

[0075] The application also provides an electrochemical device comprising the winding core structure of the above-mentioned embodiment 1. Since the electrochemical device adopts all the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0076] It should be noted that the electrochemical device of the present embodiment includes any device in which an electrochemical reaction occurs to convert chemical energy and electrical energy into each other, and specific non-limiting examples include all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors. In particular, the electrochemical device is a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery.

[0077] It should be noted that the battery mainly works by moving metal ions between the anode and the cathode. In the present application, taking a lithium battery as an example, the anode 10 includes the current collector 11 and the active material layer 12 of embodiment 1, the material of the current collector 11 can be copper, and the active material layer 12 can be a carbon-based material (such as graphite) or a silicon-based material and an alloy material, etc.; the cathode 20 includes a cathode current collector and a cathode active material layer, the cathode current collector has a functional area, and the cathode active material layer is coated on the functional area of the surface of the cathode current collector; the material of the cathode current collector can be aluminum, and the cathode active material layer can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. The electrolyte is a material with good ion conductivity, such as an aqueous solution of acid, base or salt, organic or inorganic non-aqueous solution, molten salt or solid electrolyte, etc.

[0078] Among them, the battery (Battery) refers to a cup, a groove or other container (such as a shell) or part of the space of a composite container containing an electrolyte solution and a metal electrode to generate current, a device that can convert chemical energy into electrical energy; batteries are divided into anodes and cathodes. With the progress of science and technology, batteries refer to small devices that can generate electricity, such as solar cells. The performance parameters of the battery mainly include electromotive force, capacity, specific energy and resistance. Battery principle: In a chemical battery, the direct conversion of chemical energy into electrical energy is the result of spontaneous oxidation and reduction reactions inside the battery, which occur at two electrodes.

[0079] In addition, the rechargeable battery is also called a charging battery or a storage battery, which refers to a battery that can be activated by charging after discharging. By utilizing the reversibility of chemical reactions, a new battery can be formed, that is, after a chemical reaction is converted into electrical energy, the chemical system can be repaired by electrical energy, and then the chemical reaction is converted into electrical energy.

[0080] Embodiment 3

[0081] The application also provides an electronic device comprising the electrochemical device of embodiment 2. Since the electronic device adopts all the technical solutions of all the embodiments, it at least has all the beneficial effects brought by the technical solutions of the embodiments, which will not be repeated here.

[0082] It should be noted that the electronic device of the present embodiment is not particularly limited, and it can be any electronic device known in the prior art. The use of the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art. According to some embodiments of the present application, the electronic device includes but is not limited to a mobile phone, a mobile phone, a smart phone, a notebook computer, a tablet computer, a wearable device, a smart watch, a smart bracelet, smart glasses, a mobile power supply, a television, a game console, a gamepad, a digital camera, a smart speaker, earphones, a keyboard, a mouse, a display, a drone, a sound system, a household appliance, a toy, a power tool, a car, a motorcycle, an electric bicycle, a bicycle, a robot, a robotic dog, an industrial robot, a humanoid robot, etc.

[0083] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and replacements can be made, which should be considered as the protection scope of the present application. The above shows and describes the basic principles, main features and advantages of the present application, and it is obvious for those skilled in the art that the present application is not limited to the details of the preferred embodiments, and the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, therefore all changes falling within the meaning and scope of the equivalent elements of the claims should be included in the present application.

[0084] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the specification is described in this way only for the sake of clarity, those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A core structure comprising a laminated structure formed by sequentially stacking an anode electrode (10), a diaphragm, and a cathode electrode (20); characterized in that: The stacked structure is wound around an elliptical trajectory (40) to form the core structure; The anode electrode (10) has a first winding start end (101) at one end near the elliptical trajectory (40), and the cathode electrode (20) has a second winding start end (201) at one end near the elliptical trajectory (40). The angle between the first winding start end (101) and the second winding start end (201) relative to the center of the elliptical trajectory (40) is θ, which satisfies: 90°≤θ<180°.

2. The core structure according to claim 1, characterized in that, The stacked structure has a first direction (X), a second direction (Y) and a third direction (Z) that are perpendicular to each other. The stacked structure is wound in the second direction (Y). The major semi-axis of the elliptical trajectory (40) is a and the minor semi-axis is b. In the stacked structure, the distance between the first winding start end (101) and the second winding start end (201) along the second direction (Y) is Q; satisfying: Q≥1 / 2πb+ab; and the orthogonal projection of the cathode electrode (20) along the third direction (Z) falls into the anode electrode (10).

3. The core structure according to claim 1, characterized in that, The elliptical trajectory (40) has a major axis (41) and a minor axis (42), with the first winding start end (101) located on the major axis (41) and the second winding start end (201) located on the minor axis (42). And / or, The first winding start end (101) is located on the short axis (42), and the second winding start end (201) is located on the long axis (41).

4. The core structure according to claim 2, characterized in that, In the stacked structure, the anode electrode (10) comprises: The current collector (11) has a functional area (111) and an empty foil area (112) adjacent along the first direction (X); An active material layer (12) is disposed on at least one side of the current collector (11) along the third direction (Z), and the active material layer (12) is coated on the functional area (111); The active material layer (12) is provided with a plurality of grooves (121) extending along the first direction (X), and the plurality of grooves (121) are spaced apart along the second direction (Y).

5. The core structure according to claim 4, characterized in that, Along the third direction (Z), the thickness of the active material layer (12) is B, and the depth of the groove (121) is H, satisfying: 0 < H ≤ 0.5B.

6. The core structure according to claim 4, characterized in that, Along the second direction (Y), the distance between two adjacent grooves (121) is P, which satisfies: 0 < P ≤ 10 μm.

7. The core structure according to claim 4, characterized in that, Along the second direction (Y), the width of the groove (121) is W, which satisfies: 0 < W ≤ 100 μm.

8. The core structure according to claim 4, characterized in that, Along the first direction (X), the length of the active material layer (12) is A, and the length of the groove (121) is L, satisfying: 0 < L ≤ A.

9. An electrochemical device, characterized in that, Includes the core structure as described in any one of claims 1-8.

10. An electronic device, characterized in that, Includes the electrochemical device as described in claim 9.

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