Battery monomer, battery device and electric device

Abstract

The invention provides a battery monomer, a battery device and a power utilization device. Each single battery comprises a shell and an electrode assembly, the electrode assembly is accommodated in the shell and comprises a positive pole piece, a negative pole piece and an ion absorption part, the positive pole piece and the negative pole piece are wound in the winding direction and form a bending area, the ion absorption part is arranged on the outer side of the negative pole piece, and at least part of the ion absorption part is located in the bending area; and the ion absorption piece is used for absorbing ions separated from the inner side of the adjacent positive pole piece. According to the invention, the reliability of the battery monomer can be effectively improved.

Description

Technical Field

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

[0002] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0003] In the development of battery technology, the reliability of individual battery cells directly affects the reliability, cost of use, and user experience of end products. Therefore, how to effectively improve the reliability of individual battery cells is a continuous technical challenge in battery technology. Summary of the Invention

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, which can effectively improve the reliability of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, which includes a housing and an electrode assembly. The electrode assembly is housed in the housing and includes a positive electrode, a negative electrode, and an ion absorber. The positive and negative electrode are wound along a winding direction to form a bending region. The ion absorber is disposed on the outside of the negative electrode, and at least a portion of the ion absorber is located in the bending region. The ion absorber is used to absorb ions that escape from the inside of the adjacent positive electrode.

[0006] The above technical solution introduces an ion absorber capable of absorbing and consuming active ions in the bending region of the electrode assembly. The ion absorber can absorb some of the ions that are released from the inside of the adjacent positive electrode sheet, reducing the overall content of active ions in the bending region. This is equivalent to increasing the CB value of the bending region of the electrode assembly, thereby reducing the risk of ion precipitation in the bending region of the electrode assembly and improving the reliability of the battery cell.

[0007] In some embodiments of the first aspect, the negative electrode includes a negative current collector and a first active material layer, the first active material layer being disposed outside the negative current collector. The ion absorber includes a first absorber, the first absorber being disposed on the first active material layer.

[0008] The above technical solution, by setting the first absorber on the first active material layer, can not only reduce the risk of local short circuit caused by direct contact between the first absorber and the positive electrode, but also form the first absorber simultaneously in the coating process of the negative electrode, which helps to simplify the overall manufacturing process of the battery cell and reduce costs.

[0009] In some embodiments of the first aspect, the first absorber is attached to the side surface of the first active material layer facing away from the negative electrode current collector.

[0010] The above technical solution can reduce the difficulty of preparing the first absorber, simplify the preparation process, and help reduce the overall production cost of the battery cell.

[0011] In some embodiments of the first aspect, the first active material layer includes a first body portion and a first recess, the first recess being recessed relative to the side surface of the first body portion facing away from the negative electrode current collector, and at least a portion of the first absorber is accommodated in the first recess.

[0012] The above technical solution reduces the space occupancy of the first absorber by introducing a first recess to accommodate at least part of the first absorber, thereby increasing the energy density of the battery cell.

[0013] In some embodiments of the first aspect, the first active material layer includes a first active material, the first absorbent includes a first active material and a second active material, and the first active material and the second active material in the first absorbent are mixed together.

[0014] The above technical solution can not only improve the stability of the first adsorption element, but also improve the overall consistency of the negative electrode sheet, so as to reduce the interference effect of the first adsorption element on the winding of the negative electrode sheet.

[0015] In some embodiments of the first aspect, the first active material layer includes a first active material, the first absorbent includes a second active material, and the areal density a2 of the second active material and the areal density a1 of the first active material satisfy the relationship: 0.005≤a2 / a1≤3.

[0016] The above technical solution, by setting the ratio between the areal density a2 of the second active material and the areal density a1 of the first active material to satisfy the above relationship, can reduce the risk of ion deposition in the bending region of the electrode assembly while reducing the impact on the electrochemical performance of the battery cell.

[0017] In some embodiments of the first aspect, the areal density a2 of the second active material and the areal density a1 of the first active material satisfy the relationship: 0.01≤a2 / a1≤1.

[0018] This can further enhance the balance between reducing the risk of ion deposition in the bending region of the electrode assembly and reducing the impact on the electrochemical performance of the battery cells.

[0019] In some embodiments of the first aspect, the positive and negative electrode sheets are wound along the winding direction to form a straight region, which is connected to the bending region. The dimension b1 of the first absorber along the winding direction and the length b2 of the straight region satisfy the relationship: 0.5mm ≤ b1 ≤ 2*b2.

[0020] The above technical solution, by setting the dimension b1 of the first absorber along the winding direction and the length b2 of the straight region to satisfy the above relationship, can provide tolerance space for the manufacturing process of the electrode assembly, thereby improving the success rate of setting the first absorber in the bending region while reducing the impact on the electrochemical performance of the battery cell.

[0021] In some embodiments of the first aspect, the dimension b1 of the first absorber along the winding direction and the length b2 of the straight region satisfy the relationship: 1mm ≤ b1 ≤ b2.

[0022] This approach can further enhance the success rate of placing the first absorber in the bending region while minimizing its impact on the electrochemical performance of the battery cells.

[0023] In some embodiments of the first aspect, the electrode assembly further includes a spacer disposed between the positive and negative electrode plates. The ion absorber includes a second absorber disposed on the side of the spacer adjacent to the outer side of the negative electrode plate.

[0024] The above technical solution, by placing the second absorber on the separator, can not only reduce the space occupied by the second absorber on the active material layer on the negative electrode sheet and reduce the impact on the electrochemical performance of the battery cell, but also reduce the impact of the second absorber on the structural consistency of the negative electrode sheet and reduce the risk of damage to the negative electrode sheet due to uneven stress distribution during the winding process.

[0025] In some embodiments of the first aspect, the second absorber is attached to the side surface of the separator adjacent to the outer side of the negative electrode sheet.

[0026] The above technical solution can reduce the difficulty of preparing the second absorber, simplify the preparation process, and help reduce the overall production cost of the battery cell.

[0027] In some embodiments of the first aspect, the separator includes a second body portion and a second recess, the second recess being recessed relative to a side surface of the second body portion adjacent to the outer side of the negative electrode sheet, and at least a portion of the second absorber is accommodated in the second recess.

[0028] The above technical solution reduces the space occupancy of the second absorber by introducing a second recess to accommodate at least part of the second absorber, thereby increasing the energy density of the battery cell.

[0029] In some embodiments of the first aspect, the negative electrode includes a negative current collector and a first active material layer, the first active material layer being disposed outside the negative current collector. The first active material layer includes a first active material, and the second absorber includes a third active material, the areal density a3 of the third active material and the areal density a1 of the first active material satisfying the relationship: 0.005≤a3 / a1≤1.

[0030] The above technical solution sets the ratio between the areal density a3 of the third active material and the areal density a1 of the first active material to satisfy the above relationship, which can reduce the risk of ion precipitation in the bending area of ​​the electrode assembly while reducing the impact on the electrochemical performance of the battery cell.

[0031] In some embodiments of the first aspect, the areal density a3 of the third active material and the areal density a1 of the first active material satisfy the relationship: 0.01≤a3 / a1≤0.25.

[0032] This can further enhance the balance between reducing the risk of ion deposition in the bending region of the electrode assembly and reducing the impact on the electrochemical performance of the battery cells.

[0033] In some embodiments of the first aspect, there are multiple ion absorbers, which are spaced apart along the winding direction.

[0034] The above technical solution sets the number of ion absorbers to multiple, which can improve the design flexibility of the entire battery cell through the flexible layout of multiple ion absorbers.

[0035] In some embodiments of the first aspect, the negative electrode sheet includes a plurality of negative electrode bends located in the bending region, wherein at least the two innermost negative electrode bends of the electrode assembly are provided with ion-absorbing elements.

[0036] The above technical solution can further reduce the risk of lithium plating in the bending area of ​​the electrode assembly by specifically placing the ion absorber on at least the two negative electrode bends located at the innermost part of the electrode assembly.

[0037] In some embodiments of the first aspect, multiple negative electrode bends are provided with ion-absorbing elements.

[0038] This can further reduce the risk of lithium plating in the bending areas of the electrode assembly.

[0039] In some embodiments of the first aspect, the ion absorber is entirely located in the bending region.

[0040] The above technical solution only sets the ion absorber in the bending area, so that the dimension of the ion absorber along the winding direction is relatively short, thereby improving the preparation efficiency of the negative electrode sheet and reducing the cost.

[0041] In some embodiments of the first aspect, the positive and negative electrode sheets are wound along the winding direction to form a straight region, which is connected to the bending region, and part of the ion absorber is located in the straight region.

[0042] This can reduce the risk of lithium plating in the flat region of the electrode assembly due to the reduction of the CB value of some ions that escape from the inside of the positive electrode plate located in the bending region and move to the flat region, which would prevent the ion absorber from absorbing and consuming them.

[0043] In some embodiments of the first aspect, one end of the ion absorber along the winding direction is located in the bending region, and the other end of the ion absorber along the winding direction is located in the straight region.

[0044] The ion-absorbing element passes through the junction of the straight and bent regions, which makes the negative electrode sheet have good structural consistency at the junction of the straight and bent regions. This reduces the risk of the negative electrode sheet breaking due to uneven stress distribution at the junction of the straight and bent regions during the winding process.

[0045] In some embodiments of the first aspect, the ion absorber passes through a bending region, and both ends of the ion absorber along the winding direction are located in a straight region.

[0046] The above technical solution can further increase the size of the ion absorber along the winding direction, so that the ion absorber can pass through the entire bending area, thereby further reducing the risk of lithium plating in the bending area of ​​the electrode assembly.

[0047] In some embodiments of the first aspect, the capacity of active material per unit area on the inner side of the positive electrode is less than or equal to the capacity of active material per unit area on the outer side of the negative electrode.

[0048] The electrode assembly of the above-mentioned technical solution has a more reasonable arrangement of active materials in the electrode sheets, which is more economical and reduces the risk of lithium plating.

[0049] In some embodiments of the first aspect, the ion absorber comprises fluorinated carbon.

[0050] The above technical solution uses fluorinated carbon as the main material to prepare ion absorbers. After fluorinated carbon absorbs lithium ions, the resulting lithium fluoride exhibits electrochemical inertness, has no subsequent side reactions, and has excellent stability.

[0051] Secondly, this application provides a battery device that includes a battery cell provided in any of the embodiments of the first aspect.

[0052] Thirdly, this application provides an electrical device that includes a battery cell provided in any embodiment of the first aspect or a battery device provided in any embodiment of the second aspect, wherein the battery cell or battery device is used to store or provide electrical energy.

[0053] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0054] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0055] Figure 1 These are schematic diagrams of the vehicle structure provided in some embodiments of this application;

[0056] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application;

[0057] Figure 3 This is a schematic diagram of the structure of a battery module provided in some embodiments of this application;

[0058] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell provided in some embodiments of this application;

[0059] Figure 5 This is a front view of the electrode assembly of a battery cell provided in some embodiments of this application;

[0060] Figure 6 for Figure 5 Schematic diagram of the cross-sectional structure along AA;

[0061] Figure 7 for Figure 6 A magnified schematic diagram of the local structure at point H;

[0062] Figure 8 This is a front view schematic diagram of the electrode assembly of another battery cell provided in some embodiments of this application;

[0063] Figure 9 for Figure 8 Schematic diagram of the cross-sectional structure along BB;

[0064] Figure 10 for Figure 9 A magnified schematic diagram of the local structure at point L;

[0065] Figure 11This is a front view structural schematic diagram of an electrode assembly for another battery cell provided in some embodiments of this application;

[0066] Figure 12 for Figure 11 Schematic diagram of the cross-sectional structure along CC;

[0067] Figure 13 for Figure 12 A magnified schematic diagram of the local structure at point V;

[0068] Figure 14 A front view schematic diagram of an electrode assembly for a battery cell provided in some embodiments of this application;

[0069] Figure 15 for Figure 14 Schematic diagram of the cross-sectional structure along DD;

[0070] Figure 16 for Figure 15 A magnified schematic diagram of the structure at point W.

[0071] The reference numerals in the detailed embodiments are as follows:

[0072] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Housing space; 6. Battery module; 7. Battery cell;

[0073] 10. Outer casing;

[0074] 20. Electrode assembly; 21. Bending area; 22. Straight area;

[0075] 30. Positive electrode plate;

[0076] 40. Negative electrode sheet; 40a. Negative electrode bending portion; 40b. Negative electrode straight portion; 41. Negative electrode current collector; 42. First active material layer; 421. First main body portion; 422. First recessed portion;

[0077] 50. Ion absorber; 50a. First absorber; 50b. Second absorber;

[0078] 60. Spacer; 61. Second main body; 62. Second recess;

[0079] K, winding direction. Detailed Implementation

[0080] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0082] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0084] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0085] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0086] In this application, "multiple" means two or more (including two).

[0087] In this application, the term "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0088] In this embodiment of the application, the battery cell can be a secondary battery cell, which refers to a battery cell that can be used again after being discharged by recharging to activate the active materials.

[0089] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., but the embodiments of this application are not limited to this.

[0090] A single battery cell typically includes an electrode assembly. The electrode assembly consists of a positive electrode and a negative electrode. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes.

[0091] 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.

[0092] 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.

[0093] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0094] 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 NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0095] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, 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, a positive electrode active material is filled and / or deposited within the foamed metal.

[0096] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0097] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0098] 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.

[0099] 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.

[0100] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. 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 battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0101] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0102] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0103] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0104] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0105] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0106] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0107] 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.

[0108] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0109] Liquid electrolytes include electrolyte salts and solvents.

[0110] In some embodiments, the electrolyte salt may be selected from 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.

[0111] In some embodiments, the solvent may be selected from at least one of 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 of 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.

[0112] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0113] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0114] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0115] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0116] As an example, inorganic solid electrolytes can be 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 phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0117] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0118] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0119] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0120] In some implementations, the electrode assembly is a stacked structure.

[0121] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0122] 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.

[0123] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0124] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0125] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0126] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0127] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0128] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0129] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0130] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0131] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0132] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0133] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0134] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0135] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0136] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0137] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0138] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0139] 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.

[0140] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0141] With the development of new energy technologies, batteries are being used more and more widely, for example in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools.

[0142] In the development of battery technology, the reliability of individual battery cells directly affects the reliability, cost of use, and user experience of end products. For typical battery cells, improper arrangement of active materials in the electrode plates of the electrode assembly can easily lead to lithium plating risk, seriously affecting the reliability of the battery cell.

[0143] The wound electrode assembly includes a flat region and a bent region. The thickness of the active material layer on the inner side of the flat region of the positive electrode is equal to the thickness of the active material layer on the inner side of the bent region of the positive electrode, and both the inner and outer active material layers of the flat and bent regions of the positive electrode are made of the same material. The thickness of the active material layer on the outer side of the flat region of the negative electrode is equal to the thickness of the active material layer on the outer side of the bent region of the negative electrode, and both the outer and outer active material layers of the flat and bent regions of the negative electrode are made of the same material.

[0144] In the bending region, the radius of the inner active material layer of the positive electrode is larger than the radius of the outer active material layer of the negative electrode located inside the positive electrode; that is, the radius of the outer active material layer of the negative electrode is smaller than the radius of the inner active material layer of the positive electrode located outside the negative electrode. In the straight region, the inner active material layer of the positive electrode is positioned correspondingly to the outer active material layer of the negative electrode.

[0145] When the capacity design of the inner active material layer in the flat region of the positive electrode meets the requirements, an excessive amount of active material in the inner bending region of the positive electrode makes the negative electrode, located inside the positive electrode, prone to lithium plating. Conversely, when the capacity design of the outer active material layer in the flat region of the negative electrode meets the requirements, an insufficient amount of active material in the outer bending region of the negative electrode is prone to causing lithium plating. Therefore, this type of electrode assembly, with its unreasonable arrangement of active materials in the electrodes, is prone to lithium plating risks, seriously affecting the reliability of the battery cell.

[0146] Based on the above considerations, this application provides a battery cell, which includes a housing and an electrode assembly. The electrode assembly is housed in the housing and includes a positive electrode, a negative electrode, and an ion absorber. The positive and negative electrode are wound along a winding direction to form a bending region. The ion absorber is disposed on the outside of the negative electrode, and at least a portion of the ion absorber is located in the bending region. The ion absorber is used to absorb ions that escape from the inside of the adjacent positive electrode.

[0147] The above technical solution introduces an ion absorber capable of absorbing and consuming active ions in the bending region of the electrode assembly. The ion absorber can absorb some of the ions that are released from the inside of the adjacent positive electrode sheet, reducing the overall content of active ions in the bending region. This is equivalent to increasing the CB value of the bending region of the electrode assembly, thereby reducing the risk of ion precipitation in the bending region of the electrode assembly and improving the reliability of the battery cell.

[0148] The battery cell provided in the embodiments of this application is described below with reference to the accompanying drawings.

[0149] Figure 1The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0150] Continue to refer to Figure 1 The vehicle 1 is equipped with a battery device 2, which may be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0151] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0152] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0153] Figure 2 An exploded schematic diagram of a battery device provided in some embodiments of this application.

[0154] Continue to refer to Figure 2 The battery device 2 includes a housing 5 and individual battery cells, with the individual battery cells housed within the housing 5.

[0155] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0156] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0157] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0158] In battery device 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells are connected in both series and parallel. Multiple battery cells can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells is housed in housing 5. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed manner to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed manner to form a whole assembly, which is then housed in housing 5.

[0159] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0160] In some embodiments, continue to refer to Figure 3 The battery cells 7 are multiple, and these cells are first connected in series, parallel, or in a mixed manner to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or in a mixed manner to form a whole, which is housed in the casing.

[0161] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0162] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell provided in some embodiments of this application. Figure 5 This is a front view schematic diagram of the electrode assembly of a battery cell provided in some embodiments of this application. Figure 6 for Figure 5 A schematic diagram of the cross-sectional structure along AA. Figure 7 for Figure 6 A magnified schematic diagram of the structure at point H.

[0163] Continue to refer to Figures 4 to 7 This application provides a battery cell 7, which includes a housing 10 and an electrode assembly 20. The electrode assembly 20 is housed in the housing 10 and includes a positive electrode 30, a negative electrode 40, and an ion absorber 50. The positive electrode 30 and the negative electrode 40 are wound along a winding direction K to form a bending region 21. The ion absorber 50 is disposed on the outside of the negative electrode 40, and at least a portion of the ion absorber 50 is located in the bending region 21. The ion absorber 50 is used to absorb ions that escape from the inside of the adjacent positive electrode 30.

[0164] Exemplarily, the housing 10 is a component used to form the internal environment of the battery cell 7. The formed internal environment can accommodate the electrode assembly 20, electrolyte, and other components. Optionally, the housing 10 can be, but is not limited to, made of metallic or non-metallic materials. For example, metallic materials can be copper, aluminum, or stainless steel; non-metallic materials can be polyethylene, polypropylene, or polyvinyl chloride.

[0165] Electrode assembly 20 is the component in the battery cell 7 where electrochemical reactions occur. Electrode assembly 20 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of electrode assembly 20, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs can be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0166] In this embodiment, the winding direction K is the direction in which the positive electrode 30 and the negative electrode 40 are wound circumferentially from the inside out. Figure 6 In this configuration, the winding direction K is counterclockwise. It can be understood that, to a certain extent, the winding direction K is parallel to the length direction of the positive electrode 30 and the negative electrode 40.

[0167] The outer side of the negative electrode 40 refers to the side of the negative electrode 40 facing away from the winding axis, and the inner side of the negative electrode 40 refers to the side of the negative electrode 40 facing the winding axis. The outer side of the positive electrode 30 refers to the side of the positive electrode 30 facing away from the winding axis, and the inner side of the positive electrode 30 refers to the side of the positive electrode 30 facing the winding axis.

[0168] The phrase "at least part of the ion absorber 50 is located in the bending region 21" means that the ion absorber 50 may be entirely located in the bending region 21, or a portion of the ion absorber 50 may be located in the bending region 21 and another portion in the straight region 22.

[0169] It should be noted that the number of turns of the electrode assembly 20 can be one or more. The electrode assembly 20 includes two bending regions 21, and a straight region 22 is connected between the two bending regions 21. When the number of turns of the electrode assembly 20 is N, the negative electrode sheet 40 includes N layers of negative electrode bending portions 40a in each bending region 21, that is, the entire electrode assembly 20 includes 2N layers of negative electrode bending portions 40a, and the negative electrode sheet 40 includes 2N layers of negative electrode straight portions 40b in the straight region 22, where N is an integer.

[0170] Of course, alternatively, the number of turns of the electrode assembly 20 does not have to be an integer. The number of turns of the electrode assembly 20 can be N+M, where N is an integer and M is a non-integer. For example, N can be, but is not limited to, 4, 8, 10, or 12, and M can be, but is not limited to, 1 / 3, 1 / 2, 2 / 3, or 3 / 4. It is understood that when the number of turns of the electrode assembly 20 is not an integer, for example, when the number of turns of the electrode assembly 20 is N+M, the number of layers in the negative electrode bending portion 40a in the two bending regions 21 of the electrode assembly 20 can be the same or different; the number of layers in the negative electrode straight portion 40b in the straight region 22 of the electrode assembly 20 can be 2N, 3N, or 4N, etc.

[0171] The number of ion absorbers 50 can be one or more. For example, when there is only one ion absorber 50, at least a portion of the ion absorber 50 is configured to correspond to one of the multiple negative electrode bends 40a. That is, the entire ion absorber 50 can be configured to correspond to this single negative electrode bend 40a, or a portion of the ion absorber 50 can be configured to correspond to this single negative electrode bend 40a, and another portion can correspond to the straight negative electrode portion 40b connected to this negative electrode bend 40a.

[0172] When there are multiple ion absorbers 50, the number of ion absorbers 50 may correspond to the number of negative electrode bending portions 40a, with multiple ion absorbers 50 and multiple negative electrode bending portions 40a arranged in a one-to-one correspondence, and at least a portion of each ion absorber 50 being arranged to correspond to each negative electrode bending portion 40a.

[0173] When there are multiple ion absorbers 50, the number of ion absorbers 50 may be less than the number of negative electrode bends 40a. At least a portion of each ion absorber 50 may be provided corresponding to one of the multiple negative electrode bends 40a.

[0174] The ion absorber 50 can be connected to the outside of the negative electrode 40, the inside of the positive electrode 30, or the inside or outside of the diaphragm.

[0175] The ion absorber 50 is used to absorb ions released from the inner side of the adjacent positive electrode 30. The types of ions can be various, such as lithium ions or sodium ions. The ion absorber 50 can be, but is not limited to, materials such as fluorinated carbon, graphene, antimony sulfide, ethylenediaminetetraacetic acid, anisole, and polyoxyethylene.

[0176] Optionally, the ion absorber 50 may be, but is not limited to, a sheet structure, a coating structure, a particle structure, or a fiber structure, and can be selected according to the actual application environment.

[0177] The above technical solution introduces an ion absorber 50 capable of absorbing and consuming active ions into the bending region 21 of the electrode assembly 20. The ion absorber 50 can absorb a portion of the ions that escape from the inner side of the adjacent positive electrode 30, thereby reducing the overall content of active ions in the bending region 21. This is equivalent to increasing the CB value of the bending region 21 of the electrode assembly 20, thereby reducing the risk of ion precipitation in the bending region 21 of the electrode assembly 20 and improving the reliability of the battery cell 7.

[0178] Wherein, CB (Cell Balance) is the ratio of the capacity of the negative electrode active material per unit area to the capacity of the positive electrode active material per unit area. For example, the CB (Cell Balance) value of the active material on the outer side of the negative electrode bending portion 40a of the negative electrode sheet 40 is Q1 / Q2, where the capacity of the active material per unit area of ​​the active material on the outer side of the negative electrode bending portion 40a in the negative electrode sheet 40 is Q1, and the capacity of the active material per unit area of ​​the active material on the inner side of the positive electrode bending portion 30 located outside and adjacent to the negative electrode bending portion 40a is Q2.

[0179] In some embodiments, the negative electrode 40 includes a negative current collector 41 and a first active material layer 42, the first active material layer 42 being disposed on the outer side of the negative current collector 41. The ion absorber 50 includes a first absorber 50a, the first absorber 50a being disposed on the first active material layer 42.

[0180] For example, the first absorber 50a is used to absorb ions that escape from the inside of the positive electrode 30 adjacent to it. The first absorber 50a may be connected to the surface of the negative current collector 41 of the first active material layer 42, or the first absorber 50a may be at least partially embedded in the interior of the first active material layer 42.

[0181] It is understandable that both the first adsorbent and the first active material layer 42 can react with lithium ions, therefore, the chemical properties of the first adsorbent and the first active material layer 42 are similar.

[0182] Thus, by placing the first absorber 50a on the first active material layer 42, the above technical solution can not only reduce the risk of local short circuit caused by direct contact between the first absorber and the positive electrode 30, but also form the first absorber simultaneously in the coating process of the negative electrode 40, which helps to simplify the overall manufacturing process of the battery cell 7 and reduce costs.

[0183] In some embodiments, the first absorber 50a is attached to the side surface of the first active material layer 42 facing away from the negative electrode current collector 41.

[0184] For example, attachment means adhesion, coating, or spraying.

[0185] In some examples, the first absorber 50a forms a coating structure by coating the surface of the first active material layer 42 on the side facing away from the negative electrode current collector 41.

[0186] The above technical solution can reduce the difficulty of preparing the first absorber 50a, simplify the preparation process, and help reduce the overall production cost of the battery cell 7.

[0187] Figure 8 This is a front view schematic diagram of the electrode assembly 20 of another battery cell 7 provided in some embodiments of this application. Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure along BB. Figure 10 for Figure 9 A magnified schematic diagram of the structure at point L.

[0188] Continue to refer to Figures 8 to 10 In some embodiments, the first active material layer 42 includes a first main body 421 and a first recess 422, the first recess 422 being recessed relative to the side surface of the first main body 421 facing away from the negative electrode current collector 41, and at least a portion of the first absorber 50a is accommodated in the first recess 422.

[0189] For example, a portion of the first absorbent 50a may be accommodated in the first recess 422, or the entire first absorbent 50a may be accommodated in the first recess 422.

[0190] The above technical solution, by introducing a first recess 422 to accommodate at least a portion of the first absorber 50a, can reduce the space occupancy rate of the first absorber 50a, thereby increasing the energy density of the battery cell 7.

[0191] In some embodiments, the first active material layer 42 includes a first active material, and the first absorbent 50a includes a first active material and a second active material, wherein the first active material and the second active material in the first absorbent 50a are mixed together.

[0192] The first active material is a negative electrode active material. Exemplarily, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The second active material may include at least one of fluorinated carbon, graphene, antimony sulfide, ethylenediaminetetraacetic acid, anisole, and polyoxyethylene.

[0193] The mixing of the first active material and the second active material in the first absorbent 50a means that the first absorbent 50a is a mixture of the first active material and the second active material. The first absorbent 50a can be formed by adding the second active material to the first active material, or by adding the first active material to the second active material. It should be noted that the first absorbent 50a may also include other materials, not limited to the first and second active materials.

[0194] The above technical solution can not only improve the stability of the first adsorption element, but also improve the overall consistency of the negative electrode sheet 40, so as to reduce the interference of the first adsorption element on the winding of the negative electrode sheet 40.

[0195] In some embodiments, the side surface of the first absorber 50a facing away from the negative electrode current collector 41 is flush with the side surface of the first active material layer 42 facing away from the negative electrode current collector 41, which can improve the overall consistency of the negative electrode sheet 40 and reduce the risk of the negative electrode sheet 40 breaking during the winding process.

[0196] In some embodiments, the first active material layer 42 includes a first active material, the first absorbent 50a includes a second active material, and the areal density a2 of the second active material and the areal density a1 of the first active material satisfy the relationship: 0.005≤a2 / a1≤3.

[0197] The areal density a1 of the first active material refers to the mass of the first active material contained in a unit area of ​​the negative electrode sheet 40, and the areal density a2 of the second active material refers to the mass of the second active material contained in a unit area of ​​the first absorbent 50a. The ratio between the areal density a2 of the second active material and the areal density a1 of the first active material refers to the proportion of the second active material in the active material on the outer side of the negative electrode sheet 40 of the first absorbent 50a. The first active material is the active material in the battery cell 7 that participates in normal electrochemical reactions, and the second active material is the active material used to absorb and consume active ions to reduce the number of ions participating in normal electrochemical reactions.

[0198] As an example, a2 / a1 can be, but is not limited to, 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, etc.

[0199] Understandably, the larger the ratio between the areal density a2 of the second active material and the areal density a1 of the first active material, the more active ions the first absorber 50a can absorb and consume, and the fewer ions it can participate in the normal electrochemical reaction. Conversely, the smaller the ratio between the areal density a2 of the second active material and the areal density a1 of the first active material, the fewer active ions the first absorber 50a can absorb and consume, and the more ions it can participate in the normal electrochemical reaction.

[0200] Thus, by setting the ratio between the areal density a2 of the second active material and the areal density a1 of the first active material to satisfy the above relationship, the above technical solution can reduce the risk of ion precipitation in the bending region 21 of the electrode assembly 20 while reducing the impact on the electrochemical performance of the battery cell 7.

[0201] In some embodiments, the areal density a2 of the second active material and the areal density a1 of the first active material satisfy the relationship: 0.01 ≤ a2 / a1 ≤ 1. This can further enhance the effect of reducing the risk of ion deposition in the bending region 21 of the electrode assembly 20 and reducing the impact on the electrochemical performance of the battery cell 7.

[0202] As an example, a2 / a1 can be, but is not limited to, 0.01, 0.02, 0.03, 0.04, 0.05, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, etc.

[0203] In some embodiments, the positive electrode 30 and the negative electrode 40 are wound along the winding direction K to form a straight region 22, which is connected to the bending region 21. The dimension b1 of the first absorber 50a along the winding direction K and the length b2 of the straight region 22 satisfy the relationship: 0.5mm ≤ b1 ≤ 2*b2.

[0204] The dimension b1 of the first absorber 50a along the winding direction K can be understood as the dimension of the first absorber 50a along the length of the negative electrode sheet 40, that is, the length of the first absorber 50a. The length of the flat region 22 can be understood as the dimension of the flat region 22 along the length of the electrode assembly 20.

[0205] As an example, the dimension b1 of the first absorber 50a along the winding direction K can be, but is not limited to, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, etc.

[0206] Understandably, the larger the dimension b1 of the first absorber 50a along the winding direction K, the easier it will be to position the first absorber 50a in the bending region 21 during the winding of the negative electrode sheet 40. However, the dimension of the first absorber 50a along the winding direction K cannot exceed twice the length b2 of the straight region 22, in order to reduce the impact on the electrochemical performance of the battery cell 7.

[0207] Thus, by setting the dimension b1 of the first absorber 50a along the winding direction K and the length b2 of the straight region 22 to satisfy the above relationship, the above technical solution can provide tolerance space for the manufacturing process of the electrode assembly 20, thereby improving the success rate of setting the first absorber 50a in the bending region 21 while reducing the impact on the electrochemical performance of the battery cell 7.

[0208] In some embodiments, the dimension b1 of the first absorber 50a along the winding direction K and the length b2 of the straight region 22 satisfy the relationship: 1 mm ≤ b1 ≤ b2. This can further enhance the balance between improving the success rate of placing the first absorber 50a in the bending region 21 and reducing the impact on the electrochemical performance of the battery cell 7.

[0209] As an example, the dimension b1 of the first absorber 50a along the winding direction K can be, but is not limited to, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.7mm, 4mm, etc.

[0210] Figure 11 This is a front view schematic diagram of the electrode assembly 20 of another battery cell 7 provided in some embodiments of this application. Figure 12 for Figure 11 A schematic diagram of the cross-sectional structure along CC. Figure 13 for Figure 12 A magnified schematic diagram of the structure at point V.

[0211] Continue to refer to Figures 11 to 13 In some embodiments, the electrode assembly 20 further includes a separator 60 disposed between the positive electrode 30 and the negative electrode 40. The ion absorber 50 includes a second absorber 50b disposed on the side of the separator 60 adjacent to the outer side of the negative electrode 40.

[0212] The separator 60 is used to isolate the positive electrode 30 and the negative electrode 40 to reduce the risk of short circuit between them. The separator 60 has numerous interconnected micropores, allowing electrolyte ions to pass freely and exhibiting excellent ion permeability; therefore, the separator 60 essentially does not block ion passage. For example, the separator 60 can be made of PP (polypropylene) or PE (polyethylene), etc.

[0213] The positive electrode 30, the negative electrode 40, and the separator 60 are all strip-shaped structures. In this embodiment, the positive electrode 30, the separator 60, and the negative electrode 40 can be stacked sequentially and then wound two or more times to form the electrode assembly 20.

[0214] In some examples, the spacer 60 includes a base layer and a functional layer located on the surface of the base layer. The base layer of the spacer 60 includes at least one of polypropylene, polyethylene, ethylene-propylene copolymer, polybutylene terephthalate, etc., and the functional layer may be a mixture of ceramic oxide and adhesive.

[0215] For example, the second absorber 50b is used to absorb ions released from the inside of the adjacent positive electrode 30. The second absorber 50b may be connected to the side surface of the separator 60 facing away from the negative electrode 40, or it may be connected to the side surface of the separator 60 facing the negative electrode 40. The second absorber 50b may also be at least partially embedded inside the separator 60.

[0216] The above technical solution, by placing the second absorber 50b on the separator 60, can not only reduce the space occupied by the second absorber 50b on the active material layer on the negative electrode sheet 40 and reduce the impact on the electrochemical performance of the battery cell 7, but also reduce the impact of the second absorber 50b on the structural consistency of the negative electrode sheet 40 and reduce the risk of damage to the negative electrode sheet 40 due to uneven stress distribution during the winding process.

[0217] In some embodiments, the second absorber 50b is attached to the side surface of the separator 60 adjacent to the outer side of the negative electrode 40.

[0218] For example, attachment means adhesion, coating, or spraying.

[0219] In some examples, the second absorber 50b forms a coating structure by coating the surface of the separator 60 on the side adjacent to the outside of the negative electrode 40.

[0220] In some examples, the separator 60 includes a base layer and a functional layer located on the surface of the base layer, and the second absorber 50b is attached to the side surface of the functional layer adjacent to the outside of the negative electrode 40.

[0221] The above technical solution can reduce the difficulty of preparing the second absorber 50b, simplify the preparation process, and help reduce the overall production cost of the battery cell 7.

[0222] Figure 14 This is a front view schematic diagram of the electrode assembly 20 of a battery cell 7 provided in some embodiments of this application. Figure 15 for Figure 14 A schematic diagram of the cross-sectional structure along DD. Figure 16 for Figure 15 A magnified schematic diagram of the structure at point W.

[0223] Continue to refer to Figures 14 to 16 In some embodiments, the separator 60 includes a second body portion 61 and a second recess 62, the second recess 62 being recessed relative to the side surface of the second body portion 61 adjacent to the outer side of the negative electrode plate 40, and at least a portion of the second absorber 50b is accommodated in the second recess 62.

[0224] For example, a portion of the second absorbent 50b may be accommodated in the second recess 62, or the entire second absorbent 50b may be accommodated in the second recess 62.

[0225] In some examples, the spacer 60 includes a base layer and a functional layer located on the surface of the base layer, with a second recess 62 disposed in the functional layer.

[0226] The above technical solution, by introducing a second recess 62 to accommodate at least a portion of the second absorber 50b, can reduce the space occupancy rate of the second absorber 50b, thereby increasing the energy density of the battery cell 7.

[0227] In some embodiments, the negative electrode sheet 40 includes a negative current collector 41 and a first active material layer 42, the first active material layer 42 being disposed on the outside of the negative current collector 41. The first active material layer 42 includes a first active material, and the second absorber 50b includes a third active material. The areal density a3 of the third active material and the areal density a1 of the first active material satisfy the relationship: 0.005≤a3 / a1≤1.

[0228] For example, the third active material may include at least one of fluorinated carbon, graphene, antimony sulfide, ethylenediaminetetraacetic acid, anisole, polyoxyethylene, etc. In some examples, the third active material is the same as the second active material.

[0229] The areal density a1 of the first active material refers to the mass of the first active material contained in a unit area of ​​the negative electrode sheet 40, and the areal density a3 of the third active material refers to the mass of the third active material contained in a unit area of ​​the second adsorbent. The first active material is the active substance in the battery cell 7 that participates in normal electrochemical reactions, and the third active material is the active substance used to absorb and consume active ions to reduce the number of ions participating in normal electrochemical reactions.

[0230] As an example, a3 / a1 can be, but is not limited to, 0.005, 0.01, 0.05, 0.1, 0.15, 0.2, 0.5, 1, etc.

[0231] Understandably, the larger the ratio between the areal density a3 of the third active material and the areal density a1 of the first active material, the more active ions the second absorber 50b can absorb and consume, and the fewer ions it can participate in the normal electrochemical reaction. Conversely, the smaller the ratio between the areal density a3 of the third active material and the areal density a1 of the first active material, the fewer active ions the second absorber 50b can absorb and consume, and the more ions it can participate in the normal electrochemical reaction.

[0232] Thus, by setting the ratio between the areal density a3 of the third active material and the areal density a1 of the first active material to satisfy the above relationship, the above technical solution can reduce the risk of ion precipitation in the bending region 21 of the electrode assembly 20 while reducing the impact on the electrochemical performance of the battery cell 7.

[0233] In some embodiments, the areal density a3 of the third active material and the areal density a1 of the first active material satisfy the relationship: 0.01 ≤ a3 / a1 ≤ 0.25. This can further enhance the effect of reducing the risk of ion deposition in the bending region 21 of the electrode assembly 20 and reducing the impact on the electrochemical performance of the battery cell 7.

[0234] As an example, a3 / a1 can be, but is not limited to, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, etc.

[0235] In some embodiments, the positive electrode 30 and the negative electrode 40 are wound along the winding direction K to form a straight region 22, which is connected to the bending region 21. The dimension b3 of the second absorber 50b along the winding direction K and the length b2 of the straight region 22 satisfy the relationship: 0.5mm ≤ b3 ≤ 2*b2.

[0236] The dimension b3 of the second absorber 50b along the winding direction K can be understood as the dimension of the second absorber 50b along the length of the negative electrode sheet 40, that is, the length of the second absorber 50b. The length of the flat region 22 can be understood as the dimension of the flat region 22 along the length of the electrode assembly 20.

[0237] As an example, the dimension b3 of the second absorber 50b along the winding direction K can be, but is not limited to, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, etc.

[0238] Understandably, the larger the dimension b3 of the second absorber 50b along the winding direction K, the easier it will be to position the second absorber 50b in the bending region 21 during the winding of the negative electrode sheet 40. However, the dimension of the second absorber 50b along the winding direction K cannot exceed twice the length b2 of the straight region 22, in order to reduce the impact on the electrochemical performance of the battery cell 7.

[0239] Thus, by setting the dimension b3 of the second absorber 50b along the winding direction K and the length b2 of the straight region 22 to satisfy the above relationship, the above technical solution can provide tolerance space for the manufacturing process of the electrode assembly 20, thereby improving the success rate of setting the second absorber 50b in the bending region 21 while reducing the impact on the electrochemical performance of the battery cell 7.

[0240] In some embodiments, the dimension b3 of the second absorber 50b along the winding direction K and the length b2 of the straight region 22 satisfy the relationship: 1 mm ≤ b3 ≤ b2. This can further enhance the balance between improving the success rate of placing the second absorber 50b in the bending region 21 and reducing the impact on the electrochemical performance of the battery cell 7.

[0241] As an example, the dimension b3 of the second absorber 50b along the winding direction K can be, but is not limited to, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.7mm, 4mm, etc.

[0242] In some embodiments, the number of ion absorbers 50 is multiple, and the multiple ion absorbers 50 are arranged at intervals along the winding direction K.

[0243] For example, the number of ion absorbers 50 can be two, three, four, five, six or more, depending on the actual application environment.

[0244] In some examples, the electrode assembly 20 includes two bending regions 21, and a straight region 22 connected between the two bending regions 21. Each bending region 21 includes a plurality of stacked negative electrode bending portions 40a, and the straight region 22 includes a plurality of stacked negative electrode straight portions 40b. At least one of the plurality of negative electrode bending portions 40a is provided with a plurality of ion absorbers 50.

[0245] In some examples, the electrode assembly 20 includes two bending regions 21, and a straight region 22 connected between the two bending regions 21. Each bending region 21 includes a plurality of stacked negative electrode bending portions 40a, and the straight region 22 includes a plurality of stacked negative electrode straight portions 40b. Each negative electrode bending portion 40a is provided with an ion absorber 50.

[0246] The above technical solution sets the number of ion absorbers 50 to multiple, which can improve the design flexibility of the entire battery cell 7 through the flexible arrangement of multiple ion absorbers 50.

[0247] In some embodiments, the negative electrode sheet 40 includes a plurality of negative electrode bends 40a located in the bending region 21. Among the plurality of negative electrode bends 40a, at least the two innermost negative electrode bends 40a located in the electrode assembly 20 are provided with ion absorbers 50.

[0248] For example, the two innermost negative electrode bends 40a of the electrode assembly 20 refer to the two negative electrode bends 40a closest to the starting end of the winding from the negative electrode sheet 40 along the winding direction K of the electrode assembly 20. That is, the two negative electrode bends 40a closest to the winding axis.

[0249] It is understandable that the negative electrode sheet 40 includes multiple negative electrode bent portions 40a located in the bending region 21 and multiple negative electrode straight portions 40b located in the straight region 22. In the bending region 21, the negative electrode bent portion 40a closer to the inside of the electrode assembly 20 bears greater bending stress, and the risk of the active material layer on the outside of the negative electrode bent portion 40a is also relatively greater. This makes the lithium intercalation ability of the active material layer on the outside of the negative electrode bent portion 40a closer to the inside of the electrode assembly 20 worse. Therefore, in the bending region 21, the first active material layer 42 closer to the inside of the positive electrode bent portion and the active material layer on the outside of the negative electrode bent portion 40a are more likely to generate lithium plating risk.

[0250] Thus, by specifically placing the ion absorber 50 on at least the two innermost negative electrode bends 40a of the electrode assembly 20, the above technical solution can further reduce the risk of lithium plating in the bend region 21 of the electrode assembly 20.

[0251] In some embodiments, the negative electrode 40 includes a plurality of negative electrode bends 40a located in the bending region 21. Among the plurality of negative electrode bends 40a, ion absorbers 50 are disposed on the two innermost negative electrode bends 40a located in the electrode assembly 20. This reduces the risk of lithium plating in the bending region 21 of the electrode assembly 20 while reducing the number of ion absorbers 50, which is beneficial for cost reduction.

[0252] In some embodiments, each of the plurality of negative electrode bends 40a is provided with an ion absorber 50. This can further reduce the risk of lithium plating in the bend region 21 of the electrode assembly 20.

[0253] In some embodiments, the ion-absorbing element 50 is entirely located in the bending region 21.

[0254] As described above, the electrode assembly 20 can have one or more turns. The electrode assembly 20 includes two bending regions 21, and a straight region 22 connects the two bending regions 21. When the electrode assembly 20 has N turns, the negative electrode 40 includes N negative electrode bending portions 40a in each bending region 21, and the negative electrode 40 includes 2N positive electrode straight portions in the straight region 22, where N is an integer.

[0255] The fact that at least a portion of the ion absorber 50 in this application is located in the bending region 21 means that at least a portion of the ion absorber 50 is disposed on at least one layer of negative electrode bending portion 40a.

[0256] For ease of description, the following explanation will use the example of the ion absorber 50 being disposed on the negative electrode plate 40.

[0257] For example, when there is only one ion absorber 50, the entire ion absorber 50 may be located within a portion of a negative electrode bending section 40a, meaning that neither end of the ion absorber 50 extends beyond the ends of the negative electrode bending section 40a along the winding direction K. Alternatively, the entire ion absorber 50 may be located within the entire area of ​​a negative electrode bending section 40a, meaning that both ends of the ion absorber 50 along the winding direction K coincide with the ends of the negative electrode bending section 40a along the winding direction K.

[0258] When there are multiple ion absorbers 50, the number of ion absorbers 50 can correspond to the number of negative electrode bends 40a, with each ion absorber 50 corresponding to one of the multiple negative electrode bends 40a. Alternatively, each ion absorber 50 can be entirely located within a portion of each layer of negative electrode bends 40a, meaning that neither end of each ion absorber 50 extends beyond the ends of the corresponding negative electrode bend 40a along the winding direction K. Or, each ion absorber 50 can be entirely located within the entire area of ​​each layer of negative electrode bends 40a, meaning that both ends of each ion absorber 50 along the winding direction K coincide with the ends of the corresponding negative electrode bend 40a along the winding direction K.

[0259] When there are multiple ion absorbers 50, the number of ion absorbers 50 may be less than the number of negative electrode bends 40a. One of the multiple ion absorbers 50 may be entirely located within a portion of one of the multiple bends, meaning that neither end of this ion absorber 50 extends beyond the ends of the negative electrode bend 40a in the winding direction K. Alternatively, one of the multiple ion absorbers 50 may be entirely located within the entire area of ​​one of the multiple negative electrode bends 40a, meaning that both ends of this ion absorber 50 coincide with the ends of the negative electrode bend 40a in the winding direction K.

[0260] It is understandable that when the ion absorber 50 is disposed on the separator 60, the specific structural details are similar to those of the case where the ion absorber 50 is disposed on the negative electrode plate 40, and will not be repeated here.

[0261] The above technical solution only sets the ion absorber 50 in the bending region 21, so that the dimension of the ion absorber 50 along the winding direction K is relatively short, thereby improving the preparation efficiency of the negative electrode sheet 40 and reducing the cost.

[0262] In some embodiments, the positive electrode 30 and the negative electrode 40 are wound along the winding direction K to form a flat region 22, which is connected to the bending region 21. A portion of the ion absorber 50 is located in the flat region 22. This reduces the risk of lithium plating occurring in the flat region 22 of the electrode assembly 20 due to a decrease in the CB value of the flat region 22 caused by ions detaching from the inner side of the positive electrode 30 located in the bending region 21 moving to the flat region 22 and thus being unable to be absorbed by the ion absorber 50.

[0263] In some embodiments, one end of the ion absorber 50 along the winding direction K is located in the bending region 21, and the other end of the ion absorber 50 along the winding direction K is located in the straight region 22.

[0264] For ease of description, the following explanation will use the example of the ion absorber 50 being disposed on the negative electrode plate 40.

[0265] For example, when there is only one ion absorber 50, a portion of the ion absorber 50 may be located in a localized area of ​​a negative electrode bend 40a, and another portion of the ion absorber 50 may be located in a localized area of ​​a negative electrode straight section 40b connected to this negative electrode bend 40a. Alternatively, a portion of the ion absorber 50 may be located in the entire area of ​​a negative electrode bend 40a, and another portion of the ion absorber 50 may be located in a localized area of ​​a negative electrode straight section 40b connected to this negative electrode bend 40a.

[0266] It is understandable that when there are multiple ion absorbers 50, the setting method is roughly the same as when there is only one ion absorber 50, and will not be repeated here.

[0267] Due to the winding of the electrode assembly 20, the stress at the junction of the straight region 22 and the bent region 21 in the electrode assembly 20 is relatively large. Therefore, the above technical solution, by placing a portion of the ion absorber 50 in the bent region 21 and extending another portion to the straight region 22, means that the ion absorber 50 passes through the junction of the straight region 22 and the bent region 21. This results in better structural consistency of the negative electrode sheet 40 at the junction of the straight region 22 and the bent region 21, thereby reducing the risk of breakage of the negative electrode sheet 40 due to uneven stress distribution at the junction of the straight region 22 and the bent region 21 during the winding process.

[0268] It is understandable that when the ion absorber 50 is disposed on the separator 60, the specific structural details are similar to those of the case where the ion absorber 50 is disposed on the negative electrode plate 40, and will not be repeated here.

[0269] When the ion absorber 50 is disposed on the separator 60, the above technical solution enables the separator 60 to have good structural consistency at the junction of the straight region 22 and the bending region 21, thereby reducing the risk of the separator 60 breaking due to uneven stress distribution at the junction of the straight region 22 and the bending region 21 during the winding process.

[0270] In some embodiments, the ion absorber 50 passes through the bending region 21, and both ends of the ion absorber 50 along the winding direction K are located in the straight region 22.

[0271] For ease of description, the following explanation will use the example of the ion absorber 50 being disposed on the negative electrode plate 40.

[0272] For example, when there is only one ion absorber 50, a portion of the ion absorber 50 is located in the entire area of ​​a layer of negative electrode bending portion 40a, and another portion of the ion absorber 50 is located in portions of two negative electrode straight portions 40b connected to this layer of negative electrode bending portion 40a.

[0273] It is understandable that when there are multiple ion absorbers 50, the setting method is roughly the same as when there is only one ion absorber 50, and will not be repeated here.

[0274] The above technical solution can further increase the size of the ion absorber 50 along the winding direction K, so that the ion absorber 50 can pass through the entire bending region 21, thereby further reducing the risk of lithium plating in the bending region 21 of the electrode assembly 20.

[0275] It is understandable that when the ion absorber 50 is disposed on the separator 60, the specific structural details are similar to those of the case where the ion absorber 50 is disposed on the negative electrode plate 40, and will not be repeated here.

[0276] In some embodiments, the capacity of active material per unit area inside the positive electrode 30 is less than or equal to the capacity of active material per unit area outside the negative electrode 40.

[0277] If the capacity of active material per unit area inside the positive electrode 30 is less than the capacity of active material per unit area outside the negative electrode 40, it is less likely that there will be too much active material inside the positive electrode 30, which can reduce the risk of lithium plating.

[0278] When the active material capacity per unit area on the outer side of the negative electrode 40 meets the design requirements, that is, when the active material capacity per unit area on the outer side of the negative electrode 40 reaches the first preset value, since the active material capacity per unit area on the inner side of the positive electrode 30 is smaller than the active material capacity per unit area on the outer side of the negative electrode 40, relative to the first preset value, it is equivalent to reducing the active material capacity per unit area on the inner side of the positive electrode 30, so that lithium plating is less likely to occur in the bending area 21 of the electrode assembly 20.

[0279] For example, the capacity of active material per unit area inside the positive electrode 30 can be made smaller than the capacity of active material per unit area outside the negative electrode 40 in a variety of ways.

[0280] In some examples, the thickness of the active material layer inside the positive electrode 30 is less than the thickness of the active material layer outside the negative electrode 40, so that the active material capacity per unit area inside the positive electrode 30 is less than that on the outside of the negative electrode 40. This can be achieved by having the active material in the inner active material layer of the positive electrode 30, except for the thickness, have the same parameters as the active material in the outer active material layer of the negative electrode 40. Alternatively, the active material in the inner active material layer of the positive electrode 30, except for the thickness, can also have different parameters than those on the outer active material layer of the negative electrode 40, as long as the active material capacity per unit area of ​​the inner active material layer of the positive electrode 30 is less than that on the outer active material layer of the negative electrode 40. It should be noted that these other parameters can be, but are not limited to, the type of active material, weight ratio, and specific gravity.

[0281] In some examples, the specific capacity of the active material in the inner active material layer of the positive electrode 30 is less than the specific capacity of the active material in the outer active material layer of the negative electrode 40, so that the unit area active material capacity of the inner active material layer of the positive electrode 30 is less than that of the outer active material layer of the negative electrode 40. This can be achieved by having all parameters of the active material in the inner active material layer of the positive electrode 30, except for the specific capacity, the same as those in the outer active material layer of the negative electrode 40. Alternatively, the other parameters of the active material in the inner active material layer of the positive electrode 30, except for the specific capacity, can also be different from those in the outer active material layer of the negative electrode 40, as long as the unit area active material capacity of the inner active material layer of the positive electrode 30 is less than that of the outer active material layer of the negative electrode 40. It should be noted that other parameters of the active material can be, but are not limited to, the type, weight ratio, and thickness of the active material.

[0282] If the active material capacity per unit area inside the positive electrode 30 is equal to the active material capacity per unit area outside the negative electrode 40, since the negative electrode 40 is provided with an ion absorber 50, and at least part of the ion absorber 50 is located in the bending region 21, the ion absorber 50 can absorb some of the ions that have escaped from the inside of the adjacent positive electrode 30, thereby reducing the overall content of active ions in the bending region 21. This is equivalent to increasing the CB value of the bending region 21 of the electrode assembly 20, thereby reducing the risk of ion precipitation in the bending region 21 of the electrode assembly 20 and improving the reliability of the battery cell 7.

[0283] The electrode assembly 20 of the above technical solution has a more reasonable arrangement of active materials in the electrode sheet, which is more economical and reduces the risk of lithium plating.

[0284] In some embodiments, the ion absorber 50 comprises fluorinated carbon.

[0285] For example, under the electrochemical reaction conditions of the lithium-ion battery cell 7, fluorinated carbon has a stronger ability to bind lithium ions than the negative electrode active material. The resulting lithium fluoride is electrochemically inert, with no subsequent side reactions, and has no impact on the battery cell 7 system. Utilizing this characteristic, an ion absorber 50 capable of absorbing and consuming active ions is introduced into the bending region 21 of the electrode assembly 20. The ion absorber 50 can absorb some of the ions that have escaped from the inner side of the adjacent positive electrode 30, reducing the overall content of active ions in the bending region 21. This is equivalent to increasing the CB value of the bending region 21 of the electrode assembly 20, thereby reducing the risk of ion deposition in the bending region 21 of the electrode assembly 20 and improving the reliability of the battery cell 7.

[0286] The above technical solution uses fluorinated carbon as the main material to prepare the ion absorber 50. After fluorinated carbon absorbs lithium ions, the resulting lithium fluoride exhibits electrochemical inertness, has no subsequent side reactions, and has excellent stability.

[0287] According to some embodiments of this application, this application also provides a battery device including a battery cell 7 of any of the above schemes.

[0288] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 7 or a battery device of any of the above schemes, wherein the battery cell 7 or the battery device is used to store or provide electrical energy.

[0289] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. All technical features and optional technical features of this application can be combined to form new technical solutions.

[0290] To better understand the battery cell 7 provided in the embodiments of this application, based on the same inventive concept, embodiments of the battery cell 7 in practical applications are provided here for illustration.

[0291] This application provides a battery cell 7, which includes a housing 10 and an electrode assembly 20. The electrode assembly 20 is housed in the housing 10 and includes a positive electrode 30, a negative electrode 40, and an ion absorber 50. The positive electrode 30 and the negative electrode 40 are wound along a winding direction K to form a bending region 21. The ion absorber 50 is disposed on the outside of the negative electrode 40, and at least a portion of the ion absorber 50 is located in the bending region 21. The ion absorber 50 includes fluorinated carbon and is used to absorb ions that escape from the inside of the adjacent positive electrode 30.

[0292] The above technical solution introduces an ion absorber 50 capable of absorbing and consuming active ions into the bending region 21 of the electrode assembly 20. The ion absorber 50 can absorb a portion of the ions released from the inner side of the adjacent positive electrode 30, reducing the overall content of active ions in the bending region 21. This is equivalent to increasing the CB value of the bending region 21 of the electrode assembly 20, thereby reducing the risk of ion deposition in the bending region 21 of the electrode assembly 20 and improving the reliability of the battery cell 7. By using fluorinated carbon as the main material to prepare the ion absorber 50, the lithium fluoride product generated after the fluorinated carbon absorbs lithium ions exhibits electrochemical inertness, no subsequent side reactions, and good stability.

[0293] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The electrode assembly includes: a housing; an electrode assembly accommodated in the housing, the electrode assembly including a positive electrode tab, a negative electrode tab, and an ion absorbing member, the positive electrode tab and the negative electrode tab being wound in a winding direction and forming a bending region, the ion absorbing member being disposed outside the negative electrode tab, and at least a portion of the ion absorbing member being located in the bending region, the ion absorbing member being configured to absorb ions that are stripped from an inner side of the positive electrode tab adjacent to the ion absorbing member.

2. The battery cell of claim 1, wherein, The negative electrode tab includes a negative electrode current collector and a first active material layer disposed outside the negative electrode current collector; The ion absorbing member includes a first absorbing member disposed on the first active material layer.

3. The battery cell of claim 2, wherein, The first absorbing member is attached to a side surface of the first active material layer facing away from the negative electrode current collector.

4. The battery cell of claim 3, wherein, The first active material layer includes a first main portion and a first recessed portion recessed with respect to a side surface of the first main portion facing away from the negative electrode current collector, and at least a portion of the first absorbing member is accommodated in the first recessed portion.

5. The battery cell of claim 4, wherein, The first active material layer includes a first active material, and the first absorbing member includes the first active material and a second active material, and the first active material and the second active material in the first absorbing member are mixedly disposed.

6. The battery cell of claim 2, wherein, The first active material layer includes a first active material, and the first absorbing member includes a second active material, and a face density a2 of the second active material and a face density a1 of the first active material satisfy a relationship of 0.005 ≤ a2 / a1 ≤ 3.

7. The battery cell of claim 6, wherein, The first active material layer includes a first active material, and the first absorbing member includes a second active material, and a face density a2 of the second active material and a face density a1 of the first active material satisfy a relationship of 0.01 ≤ a2 / a1 ≤ 1.

8. The battery cell of claim 2, wherein, The positive electrode tab and the negative electrode tab are wound in a winding direction to also form a flat region, and the flat region is connected to the bending region. A dimension b1 of the first absorbing member in the winding direction and a length b2 of the flat region satisfy a relationship of 0.5 mm ≤ b1 ≤ 2*b2.

9. The battery cell of claim 8, wherein, A dimension b1 of the first absorbing member in the winding direction and a length b2 of the flat region satisfy a relationship of 1 mm ≤ b1 ≤ b2.

10. The battery cell of claim 1, wherein, The electrode assembly further includes a separator disposed between the positive electrode tab and the negative electrode tab; The ion absorbing member includes a second absorbing member disposed on a side of the separator adjacent to an outer side of the negative electrode tab.

11. The battery cell of claim 10, wherein, The second absorbing member is attached to a side surface of the separator adjacent to the outer side of the negative electrode tab.

12. The battery cell of claim 11, wherein, The separator includes a second main portion and a second recessed portion recessed with respect to a side surface of the second main portion adjacent to the outer side of the negative electrode tab, and at least a portion of the second absorbing member is accommodated in the second recessed portion.

13. The battery cell of claim 10, wherein, The negative electrode tab includes a negative electrode current collector and a first active material layer disposed outside the negative electrode current collector; The first active material layer includes a first active material, and the second absorbing member includes a third active material, and a face density a3 of the third active material and a face density a1 of the first active material satisfy a relationship of 0.005 ≤ a3 / a1 ≤ 1.

14. The battery cell of claim 13, wherein, The area density a3 of the third active material satisfies the relationship: 0.01≤a3 / a1≤0.25 with the area density a1 of the first active material.

15. The battery cell of claim 1, wherein, The number of the ion absorption members is multiple, and the multiple ion absorption members are arranged at intervals along the winding direction.

16. The battery cell of claim 1, wherein, The negative electrode tab includes multiple negative electrode bending portions in the bending area, and at least two negative electrode bending portions located at the innermost of the electrode assembly are provided with the ion absorption members.

17. The battery cell of claim 16, wherein, The multiple negative electrode bending portions are all provided with the ion absorption members.

18. The battery cell of claim 1, wherein, The ion absorption members are located in the bending area as a whole.

19. The battery cell of claim 1, wherein, The positive electrode tab and the negative electrode tab are wound along the winding direction to form a flat area, the flat area is connected to the bending area, and part of the ion absorption members are located in the flat area.

20. The battery cell of claim 19, wherein, One end of the ion absorption member along the winding direction is located in the bending area, and the other end of the ion absorption member along the winding direction is located in the flat area.

21. The battery cell of claim 19, wherein, The ion absorption member passes through the bending area, and both ends of the ion absorption member along the winding direction are located in the flat area.

22. The battery cell of claim 1, wherein, The unit area active material capacity inside the positive electrode tab is less than or equal to the unit area active material capacity outside the negative electrode tab.

23. The battery cell of any one of claims 1-22, wherein, The ion absorption member includes carbon fluoride.

24. A battery device characterized by comprising: The battery device includes multiple battery cells as claimed in any one of claims 1-23.

25. An electrical device, comprising: The battery device includes the battery cell as claimed in any one of claims 1-23 or the battery device as claimed in claim 24, and is used for storing or providing electric energy.

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