Secondary battery and electric device

Abstract

The utility model discloses a kind of secondary battery and electric device, it is related to battery technical field, secondary battery includes: battery core, the battery core includes first pole piece and second pole piece stacked and winding arrangement, the first pole piece and / or the second pole piece is provided with convex portion along its thickness direction, and recess is equipped on another the second pole piece and / or another the first pole piece adjacent with the first pole piece and / or the second pole piece where the convex portion is provided, the convex portion is embedded in the recess, and the convex portion is insulation structure. First pole piece and second pole piece are in the corner area in meshing form, can effectively inhibit the interlayer slip caused by active material volume change in charge-discharge process, can significantly reduce the condition and degree of battery core cyclic expansion deformation, while improving electrolyte impregnation uniformity, enhance the overall structural stability of battery core, in prolonging battery cycle life, improve high-temperature storage performance and prevent internal short-circuiting have excellent synergistic advantage.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a secondary battery and an electrical device. Background Technology

[0002] Lithium-ion batteries, as important energy storage devices, are widely used due to their high energy density and mature technology. However, an inherent characteristic of the wound structure is the formation of corner regions with small radii of curvature at the edges of the electrode sheets. During charging and discharging, especially under fast charging or low-temperature conditions, these regions are prone to uneven deposition of lithium ions on the negative electrode surface, forming metallic lithium, a phenomenon known as 'lithium plating', due to factors such as stress concentration, uneven current density, and limited lithium-ion transport. Lithium plating not only irreversibly consumes active lithium, leading to capacity decay and increased internal resistance, but more seriously, the growth of lithium dendrites can puncture the separator, causing internal short circuits and thermal runaway, posing a significant safety hazard.

[0003] To address the lithium plating problem at corners, existing technologies have proposed several solutions: optimizing the winding design (such as increasing the radius of curvature) significantly increases cell size and reduces volumetric energy density; improving electrolyte formulations or charging strategies has limited effectiveness under harsh conditions and may sacrifice performance; coating corner areas with protective coatings such as ceramics has been proven to effectively disperse stress, block dendrites, and improve the ion environment, but directly applying the coating to the surface significantly increases the thickness at that location, leading to an increase in the overall width of the wound cell, which is detrimental to battery miniaturization and high energy density design. Furthermore, additional hard coatings may alter interlayer friction characteristics, posing a risk of relative slippage between layers under mechanical stress, affecting the structural integrity of the cell.

[0004] Therefore, there is an urgent need to develop an innovative electrode structure design that can efficiently suppress corner lithium plating without significantly increasing or even optimizing the cell width, and simultaneously improve the interlayer structural stability of the wound cell, in order to meet the development needs of high-safety, high-energy-density, and long-life lithium-ion batteries. Utility Model Content

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, in a first aspect, this invention proposes a secondary battery that can alleviate lithium plating at corners while simultaneously addressing interlayer slippage between electrodes in the corner region, thereby improving battery performance.

[0006] Secondly, this utility model proposes an electrical device that uses the aforementioned secondary battery.

[0007] The secondary battery according to the first aspect of the present invention includes:

[0008] A battery cell, comprising a first electrode and a second electrode stacked and wound together, the battery cell having a flat region and corner regions located on both sides of the flat region;

[0009] In the corner area, the first electrode and / or the second electrode are provided with a protrusion along their thickness direction, and another second electrode and / or another first electrode adjacent to the first electrode and / or the first electrode with the protrusion is provided with a recess, the protrusion is embedded in the recess, and the protrusion is an insulating structure.

[0010] The secondary battery according to the embodiments of this utility model has at least the following beneficial effects:

[0011] In this embodiment of the secondary battery, the first and second electrodes have matching and interlocking protrusions and concave portions in the corner area, creating an interlocking structure. The protrusions and / or concave portions can be made with appropriate coatings to effectively disperse stress, prevent dendrite formation, and improve the ion environment. Simultaneously, the interlocking of the protrusions and concave portions prevents an increase in the cell width. Furthermore, the cooperation of the protrusions and concave portions has a mechanical locking and limiting effect, effectively suppressing interlayer slippage caused by volume changes of the active material during charging and discharging, and significantly reducing the occurrence and extent of cell cyclic expansion deformation. Moreover, the protrusions and concave portions form a three-dimensional constraint network between the first and second electrodes, improving electrolyte wetting uniformity and enhancing the overall structural stability of the cell. This provides excellent synergistic advantages in extending battery cycle life, improving high-temperature storage performance, and preventing internal short circuits.

[0012] Therefore, the secondary battery of this embodiment can effectively suppress corner lithium plating without significantly increasing or even optimizing the cell width, and simultaneously improve the interlayer structure stability of the wound cell, thus meeting the development needs of high-safety, high-energy-density, and long-life lithium-ion batteries.

[0013] According to some embodiments of the present invention, a plurality of the protrusions and the recesses are provided between the first electrode and the second electrode.

[0014] According to some embodiments of the present invention, in the multiple winding layers of the corner area, the protrusion and the recess are provided between each adjacent first electrode and second electrode.

[0015] According to some embodiments of the present invention, the surfaces of the protrusions and / or the recesses are smooth curved surfaces.

[0016] According to some embodiments of the present invention, both the first electrode and the second electrode include a current collector and an active material layer. The active material layer is disposed on the surface of the current collector, and the thickness of the active material layer is H. The protrusion height h of the protrusion satisfies: The depth D of the recess satisfies: Where η is the design expansion rate.

[0017] According to some embodiments of the present invention, within the same corner area, the protrusions located in different winding layers are staggered along the winding direction.

[0018] According to some embodiments of this utility model, the insulating structure is a ceramic structure or a polymer structure.

[0019] According to some embodiments of the present invention, the polymer structure includes one of PVDF, PVDF-HFP, polyimide, and PMMA.

[0020] According to some embodiments of the present invention, both the first electrode and the second electrode include a current collector and an active material layer, the active material layer being disposed on the surface of the current collector, and the recess being disposed on the active material layer.

[0021] The electrical device according to the second aspect of the present invention includes a secondary battery of any of the above embodiments.

[0022] The electrical device according to the embodiments of this utility model has at least the following beneficial effects:

[0023] The electrical device of this embodiment, by using the above-mentioned secondary battery, can effectively suppress interlayer slippage of the first electrode and the second clamping plate in the corner area during charging and discharging, which can reduce the situation of cyclic expansion deformation, improve the electrolyte wetting uniformity, improve the corner lithium plating, and enhance the overall structural stability of the battery cell, thereby extending the service life, improving high-temperature storage performance, and preventing internal short circuits.

[0024] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and some of these additional aspects and advantages will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is a schematic diagram of the winding of the first and second electrode plates in this utility model;

[0027] Figure 2 This is a schematic diagram illustrating one arrangement of the convex and concave parts in this utility model;

[0028] Figure 3 This is a schematic diagram of the fitting of the convex and concave parts in this utility model.

[0029] In the picture:

[0030] 100 - First electrode, 101 - Current collector, 102 - Active material layer;

[0031] 200 - Second electrode;

[0032] 300-Straight Zone;

[0033] 400-Corner Area;

[0034] 500-convex part, 501-concave part. Detailed Implementation

[0035] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0036] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0037] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0038] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0039] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] Reference Figures 1 to 3 This utility model provides a secondary battery, including a cell. The cell includes a first electrode 100 and a second electrode 200 stacked and wound together. The cell has a straight region 300 and corner regions 400 located on both sides of the straight region 300. It is understood that during the winding process, the first electrode 100 and the second electrode 200 include alternately connected straight sections and bent sections along the winding direction, wherein the straight sections correspond to the straight region 300 and the bent sections correspond to the corner regions 400. One of the first electrode 100 and the second electrode 200 is a cathode electrode, and the other is an anode electrode.

[0041] In the corner area 400, the first electrode 100 and / or the second electrode 200 are provided with a protrusion 500 along their own thickness direction, and the adjacent second electrode 200 and / or the first electrode 100 are provided with a recess 501 along their own thickness direction. The protrusion 500 is embedded in the recess 501, and the protrusion 500 is an insulating structure.

[0042] In this embodiment, the protrusion 500 is a structure that protrudes from the surface of the electrode, and the concave portion 501 is a structure that is concave relative to the surface of the electrode.

[0043] In the prior art, the corner area 400 is prone to interlayer slippage during charging and discharging. In this embodiment, by providing mutually interlocking protrusions 500 and concave portions 501 between the first electrode 100 and the second electrode 200, the two can be mechanically restrained, which can effectively suppress the occurrence of interlayer slippage.

[0044] Furthermore, the protrusion 500 adopts an insulating structure, rather than being formed by directly protruding from the electrode surface material, which can effectively avoid the occurrence of lithium plating problems.

[0045] Therefore, in this embodiment of the secondary battery, the first electrode 100 and the second electrode 200 are provided with matching and interlocking protrusions 500 and concave portions 501 in the corner area, so that the two are in an interlocking shape in the corner area. The protrusions 500 and / or concave portions 501 can be made with appropriate coatings, thereby effectively dispersing stress, blocking dendrites and improving the ion environment. At the same time, the interlocking of the protrusions 500 and concave portions 501 avoids the increase in the width of the cell. Meanwhile, the cooperation of the protrusions 500 and concave portions 501 has a mechanical locking and limiting effect, which can effectively suppress interlayer slippage caused by the volume change of active material during charging and discharging, and can significantly reduce the occurrence and degree of cell cycle expansion deformation. Furthermore, the setting of the protrusions 500 and concave portions 501 can form a three-dimensional constraint network between the first electrode 100 and the second electrode 200, which improves the electrolyte wetting uniformity, alleviates lithium plating at the cell corner, and enhances the overall structural stability of the cell. It has excellent synergistic advantages in extending battery cycle life, improving high-temperature storage performance and preventing internal short circuits.

[0046] Therefore, the secondary battery of this embodiment can effectively suppress corner lithium plating without significantly increasing or even optimizing the cell width, and simultaneously improve the interlayer structure stability of the wound cell, thus meeting the development needs of high-safety, high-energy-density, and long-life lithium-ion batteries.

[0047] In some embodiments of this invention, a plurality of protrusions 500 and recesses 501 are provided between the first electrode 100 and the second electrode 200 along the winding direction. The cooperation of the plurality of protrusions 500 and recesses 501 improves the locking effect of the first electrode 100 and the second electrode 200 along the winding direction. Furthermore, the provision of a plurality of protrusions 500 and recesses 501 along the winding direction is equivalent to adding a corresponding coating, which can improve stress dispersion, dendrite blocking, and ion environment improvement. It also helps maintain a uniform gap between the first electrode 100 and the second electrode 200 in the corner region 400, thereby accommodating sufficient electrolyte and helping to ensure battery life and high-temperature storage performance.

[0048] It should be noted that, since the first electrode 100 and the second electrode 200 are stacked and wound, there will be multiple winding levels in the corner area 400. Between different winding levels, the distribution spacing of the protrusions 500 and the concave portions 501 along the winding direction can be the same or different, and those skilled in the art can flexibly set it as needed.

[0049] Furthermore, the protrusions 500 and concave portions 501 can be alternately arranged. For example, along the winding direction, the first electrode 100 is alternately provided with protrusions 500 and concave portions 501, while the second electrode 200 is correspondingly provided with concave portions 501 and protrusions 500 alternately on the end face facing the first electrode 100. Within the same winding layer, along the winding direction, the distance between two adjacent protrusions 500, two concave portions 501, or protrusions 500 and concave portions 501 on the electrode can be the same or different.

[0050] In some embodiments of this utility model, a plurality of protrusions 500 and recesses 501 are provided between the first electrode 100 and the second electrode 200 along the width direction of the first electrode 100 and the second electrode 200. By employing the structural configuration of this embodiment, and through the combination of multiple protrusions 500 and recesses 501 along the width direction of the electrode, the connection strength between the first electrode 100 and the second electrode 200 can be further improved, thereby enhancing the suppression effect on interlayer slippage.

[0051] Similar to the aforementioned embodiments, the spacing along the width direction can be the same or different between different winding levels. Furthermore, within the same winding level, the spacing between the protrusions 500 and the recesses 501 can be the same or different; those skilled in the art can flexibly set this as needed.

[0052] In practical applications, the first electrode 100 can be alternately provided with protrusions 500 and concave portions 501 along its own width direction, while the second electrode 200 is provided with concave portions 501 and protrusions 500 respectively, so as to improve the interlocking strength between the two.

[0053] In some embodiments of this utility model, a plurality of protrusions 500 and recesses 501 are provided between the first electrode 100 and the second electrode 200 along the winding direction and the width direction, and the protrusions 500 and recesses 501 on the first electrode 100 and the second electrode 200 are interlocked.

[0054] In this embodiment, the first electrode 100 and the second electrode 200 are provided with protrusions 500 and recesses 501 along both the winding direction and the width direction. That is, in the corner area 400, the first electrode 100 and the second electrode 200 have multiple interlocking connection positions along both the length and width directions, which can form a uniform gap between them, which is beneficial for accommodating electrolyte. At the same time, the three-dimensional constraint shape formed by multiple protrusions 500 and recesses 501 can effectively improve the suppression effect on interlayer slippage.

[0055] In conjunction with the description of the foregoing embodiments, the first electrode 100 and the second electrode 200 form a multi-layer structure during winding, and multiple winding levels of the first electrode 100 and the second electrode 200 are formed alternately in the corner area 400, so that the inner and outer sides of the first electrode 100 simultaneously have the second electrode 200. In this regard, in some embodiments of the present invention, a protrusion 500 and a recess 501 are provided between the first electrode 100 and the adjacent inner and outer second electrode 200.

[0056] With the structural configuration of this embodiment, each pair of adjacent electrode layers is fitted and locked together by the protrusion 500 and the recess 501, which can effectively suppress interlayer slippage and thus improve cell performance.

[0057] If the innermost layer is the first electrode 100, then there is no basis for the first electrode 100 and the inner second electrode 200 to fit together with the protrusion 500 and the recess 501. Instead, the second electrode 200 has the first electrode 100 on both its inner and outer sides. Therefore, in some embodiments of this utility model, the second electrode 200 and the adjacent inner and outer second electrode 200 are provided with protrusions 500 and recesses 501.

[0058] In some embodiments of this utility model, the battery cell further includes a separator disposed between the first electrode 100 and the second electrode 200. To avoid damage to the separator when the protrusion 500 and the recess 501 are engaged, the surface of the protrusion 500 is set as a smooth curved surface in this embodiment.

[0059] A smooth curved surface means that the surface of the protrusion 500 has no sharp edges or corners, and is a curved surface with varying or constant curvature. When the protrusion 500 is inserted into the recess 501, the diaphragm is also pressed into the recess 501. In this embodiment, by setting the surface of the protrusion 500 to a smooth curved surface, the protrusion 500 can be effectively prevented from piercing the diaphragm.

[0060] Based on the structure of the above embodiments, in some embodiments of this utility model, the surface of the recess 501 is further configured as a smooth curved surface to improve the protective effect on the diaphragm. This also helps to avoid burrs being generated during the processing of the recess 501, thereby avoiding the risk of burrs piercing the diaphragm.

[0061] Combination Figure 2 In some embodiments of this utility model, both the first electrode 100 and the second electrode 200 include a current collector 101 and an active material layer 102, with the active material layer 102 disposed on the surface of the current collector 101. Along the thickness direction of the electrode, the thickness of the active material layer 102 is H, the protrusion height of the protrusion 500 is h, and the depth of the recess 501 is D.

[0062] In this embodiment, the thickness value satisfies the following relationship:

[0063] The protrusion height of the protrusion is 500. η is the design expansion rate;

[0064] Depth of recess 501 .

[0065] It is understandable that although the protrusion 500 protrudes from the surface of the active material layer 102, the concave portion 501 is correspondingly disposed on the active material layer 102 of the opposing electrode. By designing the dimensional relationship between the protrusion 500 and the concave portion 501, the thickness of the active material layer and the interlocking strength of the protrusion 500 and the concave portion 501 can be taken into account.

[0066] Among them, the design expansion rate .

[0067] While meeting the aforementioned height and depth design requirements, the overall shape of the protrusion 500 is preferably designed as a gently sloping convex hull structure, similar in surface to the upper surface formed when a droplet falls onto a plane. This avoids the formation of sharp points.

[0068] In some embodiments of this invention, within the same corner area 400, the protrusions 500 located in different winding layers are staggered along the winding direction. It is understood that when protrusions 500 and recesses 501 are provided in different winding layers, aligning the protrusions 500 along the thickness direction of the battery cell may affect the cell thickness. This embodiment, by staggering the protrusions 500 between different winding layers along the winding direction, helps to avoid affecting the cell thickness, thereby helping to ensure the energy density of the battery cell.

[0069] Of course, the protrusions 500 and concave portions 501 between different winding levels can also be staggered along the width direction of the electrode.

[0070] In some embodiments of this utility model, the insulating structure used for the protrusion 500 is a ceramic structure. Specifically, during the production of the first electrode 100 and the second electrode 200, an alumina ceramic coating is periodically dripped or coated onto the surface of the electrode, with the dripping or coating area corresponding to the bending section set for the electrode, and then cured to form the protrusion 500.

[0071] This embodiment, by employing a ceramic structure, can effectively reduce the probability of burrs puncturing the diaphragm. Furthermore, the cooperation between the protrusion 500 and the recess 501 can, to a certain extent, reduce the contact between the diaphragm and the surfaces of the first electrode 100 and the second electrode 200 with burrs, thereby effectively reducing the probability of the diaphragm being punctured by burrs.

[0072] In some embodiments of this invention, the insulating structure used for the protrusion 500 is a polymer structure. Using a polymer to fabricate the protrusion 500 also provides similar effects to a ceramic coating, effectively reducing the probability of the diaphragm being punctured by burrs while ensuring the interlocking strength.

[0073] The polymer structure can be made of one or more of PVDF, PVDF-HFP, polyimide, and PMMA, which can be flexibly selected by those skilled in the art as needed. Furthermore, when multiple protrusions 500 are provided, the multiple protrusions 500 can be made of the same material or different materials.

[0074] In some embodiments of this utility model, the secondary battery includes a cell, which includes a separator, a first electrode 100, and a second electrode 200. These three components are stacked and wound together, such that a separator exists between each pair of adjacent electrode layers. The first electrode 100 and the second electrode 200 include alternating straight sections and bent sections along the winding direction. The straight sections correspond to the straight region 300 of the cell, and the bent sections correspond to the corner region 400 of the cell. Both the first electrode 100 and the second electrode 200 include a current collector 101 and active material layers 102 disposed on opposite sides of the current collector 101. The thickness of the active material layers 102 is H.

[0075] The gap between the first electrode 100 and the second electrode 200 includes odd-numbered layer gaps and even-numbered layer gaps. The odd-numbered layer gaps are formed when the first electrode 100 and the second electrode 200 are stacked, and the even-numbered layer gaps are formed by the stacking of the first electrode 100 and the second electrode 200 during winding. The first electrode 100 includes opposing first and second surfaces, and the second electrode 200 includes opposing third and fourth surfaces. The first electrode 100 and the second electrode 200 are stacked with their first and third surfaces facing each other. The odd-numbered layer gaps are the gaps formed between the first and third surfaces, and the even-numbered layer gaps are the gaps formed when the second and fourth surfaces are wound to face each other.

[0076] In the corner region 400, the first electrode 100 has a plurality of protrusions 500 protruding from its first surface along the winding direction and width direction, and the second electrode 200 has a plurality of recesses 501 recessed from its third surface along the winding direction and width direction. The recesses 501 are opposite to the protrusions 500, so that the protrusions 500 are embedded in the recesses 501. Furthermore, from the inner layer to the outer layer of the winding layer, the number of protrusions 500 and recesses 501 in the outer layer is greater than the number of protrusions 500 and recesses 501 in the inner layer because the bending section length of the electrode increases.

[0077] The protrusion 500 is formed by coating a ceramic coating before the electrode is wound, and the recess 501 is formed by pre-pressing on the active material layer 102.

[0078] In this embodiment, the protrusion height of the protrusion 500 relative to the active material layer 102 is... , .

[0079] In this embodiment, the recess 501 is recessed to a depth relative to the active material layer 102. .

[0080] In this embodiment, the first electrode 100 and the second electrode 200 only have matching protrusions 500 and recesses 501 on their two stacked surfaces, facilitating manufacturing. At the corner area 400, the first electrode 100 and the second electrode 200, through the interlocking of the protrusions 500 and recesses 501, form a three-dimensional network constraint effect, effectively suppressing interlayer slippage between them. The cooperation of multiple protrusions 500 and recesses 501 maintains a uniform and stable gap, improving electrolyte wetting uniformity and enhancing the overall structural stability of the cell. This provides excellent synergistic advantages in extending battery cycle life, improving high-temperature storage performance, and preventing internal short circuits.

[0081] Combination Figure 3 In some embodiments of this utility model, the gap between the first electrode 100 and the second electrode 200 includes odd-numbered layer gaps and even-numbered layer gaps. The odd-numbered layer gaps are formed when the first electrode 100 and the second electrode 200 are stacked, and the even-numbered layer gaps are formed by the stacking of the first electrode 100 and the second electrode 200 during winding. The first electrode 100 includes opposing first and second surfaces, and the second electrode 200 includes opposing third and fourth surfaces. The first electrode 100 and the second electrode 200 are stacked with their first and third surfaces facing each other. The odd-numbered layer gaps are the gaps formed between the first and third surfaces, and the even-numbered layer gaps are the gaps formed when the second and fourth surfaces are wound to face each other.

[0082] In the corner region 400, the first electrode 100 of this embodiment has a plurality of protrusions 500 protruding along the winding direction and width direction on its first surface, and a plurality of recesses 501 recessed along the winding direction and width direction on its second surface. The second electrode 200 has recesses 501 corresponding to the protrusions 500 on its third surface, and protrusions 500 corresponding to the recesses 501 on its fourth surface. The first electrode 100 and the second electrode 200 are engaged between the first surface and the third surface by the protrusions 500 and the recesses 501, and between the second surface and the fourth surface by the protrusions 500 and the recesses 501. This ensures that there is an engagement constraint between each pair of adjacent winding layers, which can effectively prevent interlayer slippage and help to form a uniform gap, which is beneficial for storing electrolyte.

[0083] The embodiments of this utility model also propose an electrical device, including the secondary battery of any of the above embodiments. By applying the aforementioned secondary battery, the electrical device of this embodiment can effectively suppress interlayer slippage between the first electrode 100 and the second clamping plate in the corner region 400 during charging and discharging. This reduces cyclic expansion deformation, improves electrolyte wetting uniformity, enhances the overall structural stability of the battery cell, extends service life, improves high-temperature storage performance, and prevents internal short circuits.

[0084] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A secondary battery, characterized in that, include: A battery cell, comprising a first electrode and a second electrode stacked and wound together, the battery cell having a flat region and corner regions located on both sides of the flat region; In the corner area, the first electrode and / or the second electrode are provided with a protrusion along their thickness direction, and another second electrode and / or another first electrode adjacent to the first electrode and / or the first electrode with the protrusion is provided with a recess, the protrusion is embedded in the recess, and the protrusion is an insulating structure.

2. The secondary battery according to claim 1, characterized in that, A plurality of protrusions and recesses are provided between the first electrode and the second electrode.

3. The secondary battery according to claim 1, characterized in that, In the multiple winding layers of the corner area, the protrusion and the recess are provided between each adjacent first electrode and second electrode.

4. The secondary battery according to claim 1, characterized in that, The surfaces of the protrusions and / or the recesses are smooth curved surfaces.

5. The secondary battery according to claim 1, characterized in that, Both the first electrode and the second electrode include a current collector and an active material layer. The active material layer is disposed on the surface of the current collector, and the thickness of the active material layer is H. The protrusion height h of the protrusion satisfies: The depth D of the recess satisfies: Where η is the design expansion rate.

6. The secondary battery according to claim 1, characterized in that, Within the same corner area, the protrusions located in different winding layers are staggered along the winding direction.

7. The secondary battery according to claim 1, characterized in that, The insulating structure is a ceramic structure or a polymer structure.

8. The secondary battery according to claim 7, characterized in that, The polymer structure includes one of PVDF, PVDF-HFP, polyimide, and PMMA.

9. The secondary battery according to claim 1, characterized in that, Both the first electrode and the second electrode include a current collector and an active material layer, the active material layer being disposed on the surface of the current collector, and the recess being disposed on the active material layer.

10. An electrical device, characterized in that, Includes the secondary battery as described in any one of claims 1 to 9.

Images