Battery cell and battery

Abstract

The utility model discloses a battery cell and a battery. The battery cell comprises a positive plate, a negative plate and a diaphragm, wherein the positive plate, the diaphragm and the negative plate are sequentially laminated and wound into a winding structure; in the winding structure, each of the positive plate, the negative plate and the diaphragm is provided with a plurality of linear sections and a plurality of bent sections, and the plurality of linear sections and the plurality of bent sections are alternately arranged along the winding direction of the positive plate; a connecting part is formed at the joint of the linear section and the bent section; wherein at least one connecting part of the negative plate is provided with an elastic section; and / or; and at least one connecting part of the positive plate is provided with the elastic section. The battery cell disclosed by the utility model can effectively solve the problem of lithium precipitation at corners caused by liquid shortage due to mutual extrusion of the pole pieces.

Description

Technical Field

[0001] This utility model relates to the field of batteries, specifically to battery cells and batteries. Background Technology

[0002] Improving fast charging performance has always been a crucial direction for the development of lithium-ion battery technology. However, with the increase in charging rate, battery interface issues become particularly prominent, especially in wound lithium-ion batteries. During the manufacturing process of wound lithium-ion batteries, the winding of the cell leads to a gradual increase in the interlayer gap from the edge to the center. At the edge transition areas of the cell, the contact between the electrodes is tighter, resulting in a higher concentration of winding stress. Conversely, near the center of the cell, the electrode arrangement is looser, and the corresponding stress is relatively lower. During charge-discharge cycles, the weak corner areas of the interface, under high-rate charge-discharge cycles, experience electrolyte loss due to the expansion and mutual compression of the electrodes, leading to lithium plating at the corners. This problem not only affects the cycle stability and safety of the battery but may also lead to a loss of battery energy density and a reduction in thermal safety performance.

[0003] Traditional methods for improving battery system kinetics often come at the cost of sacrificing energy density or thermal safety. For example, increasing the amount of electrolyte or improving its formulation can enhance fast-charging performance, but this may reduce energy density. Furthermore, improving thermal safety may require the addition of auxiliary materials, which also impacts energy density. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a battery cell that can effectively solve the problem of lithium plating at corners caused by electrolyte deficiency due to mutual compression of the electrodes.

[0005] This utility model also proposes a battery having the above-mentioned battery cell.

[0006] According to a first aspect of the present invention, a battery cell includes: a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and wound into a wound structure;

[0007] In the winding structure, the positive electrode sheet, the negative electrode sheet, and the separator are all provided with multiple straight segments and multiple curved segments. Along the winding direction of the positive electrode sheet, the multiple straight segments and multiple curved segments are alternately arranged; a connecting portion is formed at the connection between the straight segments and the curved segments.

[0008] Wherein, at least one of the connecting portions of the negative electrode sheet is provided with an elastic segment;

[0009] and / or;

[0010] At least one of the connecting portions of the positive electrode is provided with the elastic segment.

[0011] The battery cell according to the embodiments of this utility model has at least the following beneficial effects: it can effectively solve the problem of lithium plating at corners caused by electrolyte deficiency due to mutual compression of the electrodes. Specifically, in the battery cell of this application, elastic segments are provided in the electrodes. These elastic regions can provide necessary buffer space when the electrodes expand, effectively reducing direct contact and compression between the electrodes, thereby avoiding electrolyte deficiency caused by compression, which leads to lithium plating at corners. Through this structural design, the stability of the internal structure of the battery can be maintained under high-rate charge and discharge conditions, reducing the risk of lithium plating, extending the battery's lifespan, and improving the overall performance and safety of the battery. Therefore, the battery cell of this application, through its electrode structure design with elastic segments, can, compared with related technologies, effectively improve the problem of lithium plating at corners caused by electrolyte deficiency due to mutual compression of the electrodes during fast charging without sacrificing other battery performance.

[0012] According to some embodiments of the present invention, multiple elastic segments are provided, and each elastic segment is respectively provided in each of the connecting parts.

[0013] According to some embodiments of the present invention, the cross-sectional shape of the elastic segment along the thickness direction of the battery cell is wave-shaped or polygonal.

[0014] According to some embodiments of the present invention, the cross-sectional shape of the elastic segment along the thickness direction of the battery cell is a waveform, and the height difference between the peak of the waveform and the straight segment is H, where 2um≤H≤200um.

[0015] According to some embodiments of this utility model, the number of peaks is N, where N≥1.

[0016] According to some embodiments of the present invention, the dimension of the elastic segment along the width direction of the battery cell is L, where 0.1mm≤L≤10mm.

[0017] According to some embodiments of the present invention, in the winding structure, the position where the straight segment and the curved segment intersect is defined as base point P0, the center point of the elastic segment in the width direction of the cell is defined as base point Z0, and the difference between base point P0 and base point Z0 along the width direction of the cell is D, -10mm≤D≤10mm.

[0018] According to some embodiments of the present invention, at least one elastic segment is provided on each side of the battery cell along the width direction of the battery cell.

[0019] According to some embodiments of the present invention, multiple elastic segments are provided at the same connecting portion.

[0020] The battery according to a second aspect of the present invention includes the battery cell described in any of the preceding claims.

[0021] The battery according to the embodiments of this utility model has at least the following beneficial effects: In the battery cell of this application, elastic segments are provided in the electrodes. These elastic regions can provide necessary buffer space when the electrodes expand, effectively reducing direct contact and compression between the electrodes, thereby avoiding electrolyte loss caused by compression, which leads to the problem of lithium plating at the corners. Through this structural design, the stability of the internal structure of the battery can be maintained under high-rate charge and discharge conditions, reducing the risk of lithium plating, extending the battery's lifespan, and improving the overall performance and safety of the battery. Therefore, the battery cell of this application, through its electrode structure design with elastic segments, can, compared with related technologies, effectively improve the problem of lithium plating at the corners caused by electrolyte loss due to mutual compression of the electrodes during fast charging without sacrificing other battery performance. Thus, the battery with the above-mentioned battery cell can effectively solve the problem of lithium plating at the corners caused by electrolyte loss due to mutual compression of the electrodes.

[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0024] Figure 1 This is a schematic diagram of the battery cell of this utility model;

[0025] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0026] Figure 3 This is a schematic diagram of the elastic segment of the first embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the elastic segment of the second embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the elastic segment of the third embodiment of the present invention.

[0029] Figure label:

[0030] Battery cell 10; electrode 100; foil 101; active material layer 102; straight section 110; bent section 120; connecting part 130; elastic section 140; diaphragm 200. Detailed Implementation

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0037] A battery typically consists of a cell. The cell includes a positive electrode, a negative electrode, and a separator. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0038] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0039] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0040] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0041] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM523), LiNi 0.5 Co 0.25Mn 0.25 O2 (also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0042] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0043] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0044] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0045] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0046] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0047] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0048] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0049] In some implementations, the battery cell also includes an isolation element disposed between the positive and negative terminals.

[0050] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0051] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0052] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0053] In some embodiments, the battery also includes an electrolyte that acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0054] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0055] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0056] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0057] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0058] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0059] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0060] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0061] In some implementations, the battery cell has a wound structure. The positive and negative electrode plates are wound into a wound structure.

[0062] In some implementations, the battery cell has a laminated structure.

[0063] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0064] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0065] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0066] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0067] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0068] In some implementations, the battery cell can be cylindrical, flat, or polygonal, etc.

[0069] In some implementations, the battery cell is provided with tabs that allow current to be drawn out of the cell. The tabs include a positive tab and a negative tab.

[0070] In some embodiments, the battery may include a casing. The casing is used to encapsulate components such as the battery cell and electrolyte. The casing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0071] As an example, the battery can be a cylindrical battery, a prismatic battery, a pouch battery, or a battery of other shapes. Prismatic batteries include, but are not limited to, square-shell batteries, blade-shaped batteries, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0072] The battery mentioned in the embodiments of this application refers to a single physical module that includes one or more batteries to provide higher voltage and capacity.

[0073] In some embodiments, the battery can be a battery module, and when there are multiple batteries, the multiple batteries are arranged and fixed to form a battery module.

[0074] In some embodiments, the battery may be a battery pack, which includes a housing and a battery, with the battery or battery module housed within the housing.

[0075] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0076] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0077] In recent years, fast charging capability has been a key objective in the technological advancement of lithium-ion batteries. However, with the increase in charging rates, the interface challenges of batteries have become more pronounced, especially in lithium-ion batteries employing a wound design. During the manufacturing process of wound lithium-ion batteries, the winding of the cell causes the gaps between layers to gradually increase from the edge to the center. At the turning points of the cell edges, the electrodes are tightly bonded, resulting in a high concentration of winding stress. Conversely, the electrodes near the center of the cell are more loosely bonded, with relatively lower stress. During rapid charging and discharging, the weaker edge areas may experience electrolyte loss due to electrode expansion and mutual compression, triggering lithium plating. This not only reduces the battery's cycle stability and safety but may also compromise its energy density and thermal safety.

[0078] In related technologies, improving battery fast-charging performance often requires sacrificing battery energy density and thermal safety. For example, increasing the electrolyte or optimizing its formulation can enhance fast-charging capability, but this may reduce battery energy density. Similarly, auxiliary materials added to enhance battery thermal safety may also affect energy density.

[0079] Therefore, there is a need for a battery cell that can effectively solve the problem of lithium plating at the corner caused by liquid shortage due to mutual compression of the electrodes, without sacrificing the battery's energy density and thermal safety.

[0080] Based on the above problems, this application proposes a battery cell that aims to solve the problems existing in the related technologies to a certain extent.

[0081] Reference Figure 1 , Figure 2 In some embodiments, the battery cell 10 includes a positive electrode 100, a negative electrode 100, and a separator 200, which are sequentially stacked and wound into a wound structure. In the wound structure, the positive electrode 100, the negative electrode 100, and the separator 200 are each provided with multiple straight segments 110 and multiple curved segments 120, which are alternately arranged along the winding direction of the positive electrode 100; a connecting portion 130 is formed at the junction of the straight segments 110 and the curved segments 120. At least one connecting portion 130 of the negative electrode 100 or at least one connecting portion 130 of the positive electrode 100 is provided with an elastic segment 140, or at least one connecting portion 130 of the negative electrode 100 and at least one connecting portion 130 of the positive electrode 100 are provided with an elastic segment 140.

[0082] The battery cell 10 of this application embodiment has at least the following beneficial effects: it can effectively solve the problem of lithium plating at corners caused by electrolyte deficiency due to mutual compression of the electrodes 100. Specifically, in the battery cell 10 of this application, elastic segments 140 are provided in the electrodes 100. These elastic segments 140 form elastic regions inside, which can provide necessary buffer space when the electrodes 100 expand. For example, if the corners of the winding structure are subjected to pressure and are squeezed together, the elastic segments 140 can generate expansion and contraction deformation to buffer the pressure on the electrodes 100 at the corners, effectively reducing direct contact and compression between the electrodes 100, thereby avoiding electrolyte deficiency caused by compression, which leads to lithium plating at corners.

[0083] It should be noted that in this application, the wound cell is approximately a cuboid, but not a rectangle in the strict sense. The width and thickness of the cell referred to in this article are for ease of understanding. In fact, the width direction of the cell can also be the width direction of the tab.

[0084] Generally, the winding structure has multiple straight segments 110 and curved segments 120, which are alternately arranged. Straight segments 110 are connected to both ends of the curved segments 120, and the connection points between the straight segments 110 and the curved segments 120 are called connecting portions 130. That is, in each turn of the positive electrode 100, negative electrode 100, or separator 200 of the winding structure, there are at least four connecting portions 130. Because the gaps between the electrode pieces 100 at the connecting portions 130 where the straight segments 110 and curved segments 120 connect are small, the contact between the electrode pieces 100 is tighter, and the winding stress is more concentrated.

[0085] This application provides an elastic segment 140 at the connection portion 130. During the high-rate charging and discharging cycle of the battery, when the electrode 100 expands and causes the electrode 100 to squeeze against each other, the elastic segment 140 undergoes elastic deformation and acts as a buffer between the electrode 100. This can largely avoid the problem of lithium plating at the corner caused by the lack of liquid due to the mutual squeezing of the electrode 100 during fast charging.

[0086] Furthermore, the elastic segment 140 can be provided separately at at least one connection portion 130 of the negative electrode 100, or separately at at least one connection portion 130 of the positive electrode 100, or both at at least one connection portion 130 of the negative electrode 100 and at least one connection portion 130 of the positive electrode 100, to effectively solve the problem of lithium plating at corners caused by liquid deficiency due to mutual compression of the electrodes 100. It should be noted that if the elastic segment 140 is provided at at least one connection portion 130 of both the positive and negative electrode 100, it is preferable that the elastic segments 140 of the positive electrode 100 and the elastic segments 140 of the negative electrode 100 are not aligned along the thickness direction of the cell 10 (i.e., the elastic segments 140 are provided at connection points in different locations). By setting the elastic segments 140 staggered in the thickness direction of the cell 10, the electrode 100 can be provided with better spatial adaptability, so that its expansion and contraction during the charging and discharging process of the battery can be effectively relieved, further improving the buffering effect and avoiding the corner lithium plating problem caused by the lack of liquid due to the mutual squeezing of the electrode 100.

[0087] This structural design allows for the maintenance of internal battery stability under high-rate charge and discharge conditions, reducing the risk of lithium plating, extending battery life, and improving overall battery performance and safety. Therefore, the cell 10 of this application, with its electrode 100 structure featuring an elastic segment 140, effectively addresses the corner lithium plating problem caused by electrolyte deficiency due to mutual compression of the electrodes 100 during fast charging, without sacrificing other battery performance characteristics, compared to related technologies.

[0088] According to some embodiments of this utility model, multiple elastic segments 140 are provided, and each elastic segment 140 is respectively provided in each connecting portion 130. Generally, the winding structure has multiple straight segments 110 and curved segments 120, which are alternately arranged. Straight segments 110 are connected to both ends of the curved segments 120, and the connection between the straight segments 110 and the curved segments 120 is the connecting portion 130. That is, in each turn of the positive electrode 100, negative electrode 100, or separator 200 of the winding structure, there are at least four connecting portions 130. Because the gap between the electrode 100 at the connecting portion 130 where the straight segments 110 and the curved segments 120 connect is small, the contact between the electrode 100 is tighter, and the winding stress is more concentrated. This application, by setting multiple elastic segments 140, provides elastic segments 140 to each connection portion 130. Compared to setting elastic segments 140 in only one connection portion 130, this further increases the number of elastic segments 140 in the electrode 100, thereby increasing the overall elastic deformation capability of the electrode 100. During the charging and discharging process of the battery, especially during high-rate cycling, when the electrode 100 expands and causes mutual compression, each elastic segment 140 undergoes elastic deformation, providing better buffering between the electrode 100s. This can largely avoid the corner lithium plating problem caused by liquid shortage due to mutual compression of the electrode 100s during fast charging.

[0089] This structural design maintains the stability of the battery's internal structure under high-rate charge and discharge conditions, reduces the risk of lithium plating, extends battery life, and improves overall battery performance and safety. Therefore, the cell 10 of this application, with its electrode 100 structure featuring an elastic segment 140, effectively addresses the corner lithium plating problem caused by electrolyte deficiency due to mutual compression of the electrodes 100 during fast charging, compared to related technologies, without sacrificing other battery performance.

[0090] According to some embodiments of this utility model, the cross-sectional shape of the elastic segment 140 along the thickness direction of the cell 10 is wave-shaped or polygonal. In this application, the elastic segment 140 can be configured as a non-linear wave-shaped or polygonal shape. By creating a non-linear buffer path inside the cell 10, the adaptability of the electrode 100 to volume changes during charging and discharging can be increased, reducing direct contact between the electrodes 100 and the resulting mechanical stress. This helps maintain a uniform distribution of the electrolyte, avoids electrolyte loss due to mutual compression caused by the expansion of the electrodes 100, thereby reducing lithium plating and improving the cycle stability of the battery.

[0091] Reference Figure 3According to some embodiments of this utility model, the cross-sectional shape of the elastic segment 140 along the thickness direction of the cell 10 is waveform, and the height difference between the peak of the waveform and the straight segment 110 is H, where 2µm ≤ H ≤ 200µm. For example, H can be 2µm, 10µm, or 200µm. In this application, the elastic segment 140 is preferably waveform-shaped. The structure of the waveform-shaped elastic segment 140 is similar to a series of intersecting waves, which allows the elastic segment 140 to undergo elastic deformation when subjected to compression or tension, thereby providing a larger surface area and stronger elastic support. At the same time, when the electrode 100 expands, the waveform-shaped elastic segment 140 can more effectively absorb stress, reducing direct contact between the electrodes 100 and the resulting mechanical stress concentration. In addition, the height (peak) of the waveform can be precisely designed and manufactured according to specific battery design requirements to adapt to different battery shapes and sizes. Furthermore, it can also improve the stability and lifespan of the battery because it can provide better shock absorption and support within a limited space. Therefore, since the elastic segment 140 has a wave-like shape, it can enhance the mechanical adaptability of the battery, optimize the electrolyte distribution, improve the cycle stability and safety of the battery, and at the same time reduce the loss of energy density and the reduction of thermal safety performance.

[0092] In addition, the height difference H between the peak of the preferred waveform and the straight line segment 110 is 2um≤H≤200um. This ensures that the peak is not too high and occupies too much space, while also ensuring sufficient elastic deformation to provide a buffering effect.

[0093] According to some embodiments of this utility model, the number of peaks is N, where N≥1. The number of peaks can be specifically set according to actual needs, and can be set to one or more. In this application, it is preferred to set multiple peaks. Multiple peaks can increase the surface area of ​​the elastic part to more effectively disperse stress, so that when subjected to compression or tension, the stress can be more evenly distributed on more peaks, which helps to reduce stress concentration on a single peak, thereby reducing material fatigue and improving the durability of the overall structure. At the same time, the design of multiple peaks can more finely adjust the elastic characteristics of the elastic segment 140 to adapt to different load conditions and motion changes. In this application, the figures show the case where the peaks of each elastic segment 140 are the same, but each peak can also be designed with different heights and spacings as needed to achieve a specific buffering effect.

[0094] According to some embodiments of this utility model, the length of the elastic segment 140 along the width direction of the cell 10 is L, where 0.1mm ≤ L ≤ 10mm. In the winding structure, the length of the elastic segment 140 cannot be too long or too short. This application preferably sets the length L of the elastic segment 140 to 0.1mm ≤ L ≤ 10mm. Thus, when L is greater than 0.1mm, the elastic segment 140 will not be too short, resulting in extremely small elastic deformation that cannot provide sufficient buffering effect. When L is less than 10mm, the elastic segment 140 will not be too long, resulting in wasted material and battery internal space. By controlling the length of the elastic segment 140, it can be ensured that it maintains its performance under repeated stretching and compression conditions, avoiding material fatigue or damage caused by excessive elongation or compression. At the same time, it helps to optimize the space utilization of the battery, making the battery assembly more compact, thereby achieving higher energy density in a limited space.

[0095] According to some embodiments of this utility model, in the winding structure, the intersection of the straight segment 110 and the curved segment 120 is defined as base point P0, and the center point of the elastic segment 140 in the width direction of the cell 10 is defined as base point Z0. Along the width direction of the cell 10, the difference between base point P0 and base point Z0 is D, where -10mm ≤ D ≤ 10mm. Similar to setting the length of the elastic segment 140 as described above, the difference D between base point P0 and base point Z0 is controlled within the range of -10mm ≤ D ≤ 10mm. That is, the center point of the elastic segment (base point Z0) is as close as possible to the connection point (base point P0) where the straight segment 110 and the curved segment 120 connect, so that the difference D between the center point of the elastic segment 140 and the connection point is 0 ± 10mm. Preferably, the center point of the elastic segment 140 coincides with the connection point between the straight segment 110 and the curved segment 120, i.e., D is 0. This allows for control over the elastic deformation range of the elastic segment 140, improving battery safety and avoiding the risk of battery rupture or internal short circuits due to excessive deformation. It also optimizes battery space utilization, making the battery assembly more compact and achieving higher energy density within a limited space.

[0096] According to some embodiments of this utility model, at least one elastic segment 140 is provided on each side of the battery cell 10 along its width direction. Specifically, providing at least one elastic segment 140 on each side of the battery cell 10 in its width direction ensures that elastic deformation can be performed on both sides, providing a certain degree of buffer space when the electrode 100 expands. For example, if the corner of the winding structure is subjected to pressure and squeezed against each other, the elastic segment 140 can generate expansion and contraction deformation to buffer the pressure on the electrode 100 at the corner, effectively reducing direct contact and squeezing between the electrode 100s, thereby avoiding electrolyte loss caused by squeezing, which could lead to lithium plating at the corner.

[0097] Reference Figure 4, Figure 5 According to some embodiments of this utility model, multiple elastic segments 140 are provided at the same connection portion 130. Depending on actual needs, if the compression caused by the expansion of the electrode 100 is severe, multiple elastic segments 140 can also be provided at the same connection portion 130 to further increase the elastic deformation capacity and buffer space, thereby effectively reducing direct contact and compression between the electrode 100s and avoiding the problem of lithium plating at corners due to electrolyte loss caused by compression. Figure 4 This is a schematic diagram of two elastic segments 140 provided at the same connection part 130 of the electrode 100. However, this diagram is only for illustration and is not a limitation of this application. For example, three, four or five elastic segments 140 may also be provided as needed. Figure 5 A schematic diagram is shown of an electrode 100 comprising a foil 101 and an active material layer 102, wherein two elastic segments 140 are provided at the same connection portion 130.

[0098] The battery according to the second aspect of the present invention includes the cell 10 of any of the above claims.

[0099] The battery according to the embodiments of this utility model has at least the following beneficial effects: In the cell 10 of this application, elastic segments 140 are provided in the electrode 100. These elastic regions can provide necessary buffer space when the electrode 100 expands, effectively reducing direct contact and compression between the electrodes 100, thereby avoiding electrolyte loss caused by compression, which leads to the problem of lithium plating at the corner. Through this structural design, the stability of the internal structure of the battery can be maintained under high-rate charge and discharge conditions, reducing the risk of lithium plating, extending the battery's service life, and improving the overall performance and safety of the battery. Therefore, the cell 10 of this application, through the electrode 100 structural design with elastic segments 140, can, compared with related technologies, effectively improve the problem of lithium plating at the corner caused by electrolyte loss due to mutual compression of the electrodes 100 during fast charging without sacrificing other battery performance. Therefore, the battery with the above-mentioned cell 10 can effectively solve the problem of lithium plating at the corner caused by electrolyte loss due to mutual compression of the electrodes 100.

[0100] 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 battery cell, characterized in that, include: A positive electrode, a negative electrode, and a separator, wherein the positive electrode, the separator, and the negative electrode are sequentially stacked and wound into a wound structure; In the winding structure, the positive electrode sheet, the negative electrode sheet, and the separator are all provided with multiple straight segments and multiple curved segments. Along the winding direction of the positive electrode sheet, the multiple straight segments and multiple curved segments are alternately arranged; a connecting portion is formed at the connection between the straight segments and the curved segments. Wherein, at least one of the connecting portions of the negative electrode sheet is provided with an elastic segment; and / or; At least one of the connecting portions of the positive electrode is provided with the elastic segment.

2. The battery cell according to claim 1, characterized in that, The elastic segment is provided in multiple ways, and each elastic segment is respectively provided in each of the connecting parts.

3. The battery cell according to claim 2, characterized in that, The cross-sectional shape of the elastic segment along the thickness direction of the battery cell is wave-shaped or polygonal.

4. The battery cell according to claim 3, characterized in that, The cross-sectional shape of the elastic segment along the thickness direction of the battery cell is a waveform, and the height difference between the peak of the waveform and the straight segment is H, where 2um≤H≤200um.

5. The battery cell according to claim 4, characterized in that, The number of peaks is N, where N≥1.

6. The battery cell according to claim 4, characterized in that, The elastic segment has a dimension L along the width direction of the battery cell, where 0.1mm ≤ L ≤ 10mm.

7. The battery cell according to claim 1, characterized in that, In the winding structure, the position where the straight segment and the curved segment intersect is defined as base point P0, and the center point of the elastic segment in the width direction of the cell is defined as base point Z0. Along the width direction of the cell, the difference between base point P0 and base point Z0 is D, where -10mm≤D≤10mm.

8. The battery cell according to claim 1, characterized in that, Along the width direction of the battery cell, at least one elastic segment is provided on each side of the battery cell.

9. The battery cell according to claim 1, characterized in that, At the same connecting portion, a plurality of elastic segments are provided.

10. A battery, characterized in that, The battery cell includes any one of claims 1 to 9.

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