Electrode assembly, battery cell, battery and electrical device

Abstract

The present disclosure provides an electrode assembly, a battery cell, a battery, and an electric device, which belong to the technical field of batteries. The electrode assembly includes a plurality of structural units, each including a first electrode sheet and a second electrode sheet, stacked along a first direction. The first electrode sheet includes a structural unit and a plurality of straight segments, with two adjacent straight segments spaced apart along the first direction and connected to one structural unit. The second electrode sheet and the first electrode sheet have opposite polarities, and the second electrode sheet and the straight segments are alternately arranged along the first direction. This structure reduces tilting of the electrode assembly during the molding process, thereby reducing the risk of misalignment between the electrode sheets and effectively improving the reliability of the electrode assembly.

Description

[Technical Field]

[0001] The present application relates to the technical field of batteries, and in particular to electrode assemblies, battery cells, batteries and electrical devices. [Background technology]

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

[0003] In battery cells, electrode assemblies are generally divided into two types: stacked and wound. Stacked electrode assemblies have the advantages of low local internal resistance and high energy density, but their reliability needs to be further improved. Therefore, how to improve the reliability of electrode assemblies is a challenge that needs to be solved in battery technology. Summary of the Invention

[0004] The embodiments of the present application provide an electrode assembly, a battery cell, a battery, and an electric device that can effectively improve the reliability of the electrode assembly.

[0005] In a first aspect, an embodiment of the present application provides an electrode assembly including a plurality of structural units stacked and arranged along a first direction, the structural units including a bent segment and a plurality of straight segments, two adjacent straight segments arranged at intervals along the first direction and connected to one bent segment, and a second electrode sheet having an opposite polarity to the first electrode sheet and arranged alternately with the straight segments along the first direction.

[0006] In the above embodiment, the electrode assembly includes a plurality of structural units, and the first electrode sheet in each structural unit has a folded structure formed by folded segments and straight segments, and the straight segments of the first electrode sheet are alternately arranged with the second electrode sheet. In this way, during manufacturing, the structural unit can be first formed using the first electrode sheet and the second electrode sheet, and then the plurality of structural units can be stacked. This reduces tilting during the forming process of the electrode assembly, thereby reducing the risk of misalignment between the electrode sheets and effectively improving the reliability of the electrode assembly.

[0007] In some embodiments, the number of straight segments of the first electrode sheet in at least one structural unit is greater than 2. In this way, the number of straight segments of the first electrode sheet in at least one structural unit is greater, which can effectively improve the manufacturing efficiency of the electrode assembly.

[0008] In some embodiments, the number of straight segments of the first electrode sheet in at least one structural unit is odd. When the number of straight segments of the first electrode sheet is odd, the number of bent segments of the first electrode sheet is even, and the number of bent segments on both sides of the structural unit perpendicular to the first direction is equal. When the first electrode sheet is subjected to a force along the first direction, both bent segments on both sides of the structural unit can deform, improving the structural stability of the first electrode sheet and reducing the difference in deformation on both sides of the structural unit, making it less likely that the structural unit will tilt, reducing the risk of misalignment between the electrode sheets, and improving the reliability of the electrode assembly.

[0009] In some embodiments, the number of straight segments of the first electrode sheet in each structural unit is greater than 2. In this way, when the dimension of the electrode assembly along the first direction is constant, the number of straight segments of the first electrode sheet in each structural unit is increased, which is advantageous for reducing the number of structural units of the electrode assembly, and further improving the manufacturing efficiency of the electrode assembly.

[0010] In some embodiments, the number of straight segments of the first electrode sheet in each structural unit is odd, so that the number of bent segments of each first electrode sheet is even, and the number of bent segments on both sides perpendicular to the first direction in each structural unit is equal, so that when the first electrode sheet is subjected to a force along the first direction, both bent segments on both sides of the structural unit can be deformed, thereby providing good structural stability for the first electrode sheet in each structural unit and further reducing the risk of tilting of the structural unit, thereby reducing the risk of tilting of the electrode assembly.

[0011] In some embodiments, the number of straight segments of the first electrode sheet in each structural unit is 3. This not only reduces the risk of the first electrode sheet being tilted during the folding process, but also ensures that the first electrode sheet in the structural unit has excellent stability after molding, reducing the risk of the electrode assembly being tilted.

[0012] In some embodiments, the number of straight segments of the first electrode sheet in at least two structural units is unequal, which allows the types of structural units in the electrode assembly to be diversified, and multiple structural units can adopt multiple combination forms, improving the versatility of the electrode assembly and enabling it to better meet market needs.

[0013] In some embodiments, the plurality of structural units include a first structural unit, a second structural unit, and a third structural unit sequentially arranged along the first direction, wherein the number of straight segments of the first electrode sheet in the first structural unit and the number of straight segments of the first electrode sheet in the third structural unit are all even numbers, and the number of straight segments of the first electrode sheet in the second structural unit is odd numbers. The number of straight segments of the intermediate second structural unit is odd, the number of straight segments of the first structural unit and the third structural unit located on both sides of the second structural unit are even numbers, and the number of bent segments on both sides perpendicular to the first direction of the second structural unit is equal, so that when a combined structure formed by the first structural unit, the second structural unit, and the third structural unit is subjected to a force along the first direction, the difference in deformation of the combined structure on both sides perpendicular to the first direction is small, resulting in better structural stability and less tilting of the combined structure.

[0014] In some embodiments, the two straight segments located at both ends of the first electrode sheet along the first direction are respectively the first straight segment and the second straight segment. In two adjacent structural units, the first straight segment in one structural unit and the second straight segment in the other structural unit are two adjacent straight segments, and along the second direction Y, one end of the first straight segment in one structural unit away from the bent segment 2312 and one end of the second straight segment in the other structural unit away from the bent segment are located on opposite sides of the electrode assembly, respectively, and the second direction is perpendicular to the first direction. The two adjacent bent segments on each side of the electrode assembly in the second direction are neither too far nor too close, resulting in a more reasonable layout, which improves the structural stability of the electrode assembly and further reduces the risk of tilting.

[0015] In some embodiments, the number of straight segments of the first electrode sheet in the structural unit is equal to the number of second electrode sheets, so that the straight segments and second electrode sheets in the structural unit correspond to each other, and the straight segments and second electrode sheets in two adjacent structural units are alternately arranged, which is advantageous for improving the electrical capacity of the battery cell.

[0016] In some embodiments, the electrode assembly further includes a third electrode sheet having the same polarity as the first electrode sheet, the third electrode sheet being provided on at least one side of the plurality of structural units along the first direction, and the third electrode sheet being adjacent to the second electrode sheet of the adjacent structural unit. This makes full use of the outermost second electrode sheet of the structural unit located at the end of the electrode assembly, which is advantageous for improving the electrical capacity of the battery cell.

[0017] In some embodiments, the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet, which makes it easier for the negative electrode sheet to cover the positive electrode sheet, reduces the risk of the positive electrode sheet protruding from the negative electrode sheet, and improves the reliability of the electrode assembly.

[0018] In some embodiments, a first tab is provided on each straight segment, and the multiple first tabs in each structural unit are aligned along the first direction, and / or a second tab is provided on each second electrode sheet, and each structural unit includes multiple second electrode sheets, and the multiple second tabs in each structural unit are aligned along the first direction. Aligning the multiple first tabs in a structural unit along the first direction facilitates busbar connection, allows the entire structural unit to be cut when cutting the first tabs, and improves cutting efficiency of the first tabs, thereby improving manufacturing efficiency. Aligning the multiple second tabs in a structural unit along the first direction facilitates busbar connection, allows the entire structural unit to be cut when cutting the second tabs, thereby improving cutting efficiency of the second tabs, thereby improving manufacturing efficiency.

[0019] In some embodiments, the structural unit further includes a separator film, and the first electrode sheet and the second electrode sheet are both combined with the separator film, and the separator film is arranged to separate the first electrode sheet and the second electrode sheet. The separator film provides insulation and separation between the first electrode sheet and the second electrode sheet, reducing the risk of internal short circuits in the electrode assembly. Because the first electrode sheet and the second electrode sheet are both combined with the separator film, the first electrode sheet, the second electrode sheet, and the separator film in the structural unit have good integrity, and the risk of misalignment between the first electrode sheet and the second electrode sheet is reduced.

[0020] In some embodiments, the folding segment is provided with a guide portion for guiding the folding of the folding segment, which allows the first electrode sheet to be folded at a predetermined position, improving the folding efficiency of the first electrode sheet, increasing the consistency of the folding position, and making the relative position between the straight segment and the second electrode sheet more accurate, thereby ensuring the reliability of the electrode assembly.

[0021] In some embodiments, the guide portion includes a groove formed in the folding segment. The folding segment is thinner in the area where the groove is formed, and the groove has a good guiding effect, so that the first electrode sheet can be easily folded at the groove to correspond to the formed folding segment. Such a guide portion has a simple structure and is easy to form.

[0022] In some embodiments, the folded segment includes a current collector and two active material layers, each of which is disposed on either side of the current collector, and at least one of which has a groove formed therein. By providing the groove in at least one of the active material layers of the folded segment, a portion of the folded segment can be thinned, which simplifies the implementation.

[0023] In some embodiments, one active material layer has a recessed groove, which can reduce the difficulty of forming the first electrode sheet.

[0024] In some embodiments, both active material layers are provided with grooves, so that the folding segment is thinner in the grooved areas and easier to fold.

[0025] In some embodiments, the guide portion further includes a through-hole penetrating the current collector, and a region of the current collector corresponding to the groove forms a non-active material layer region, and the through-hole is provided in the non-active material layer region. The arrangement of the through-hole reduces the rigidity of the non-active material layer region of the current collector, which reinforces the folding effect and further improves the folding efficiency of the first electrode sheet. Furthermore, in the battery cell, the electrolyte flows between the first electrode sheet and the second electrode sheet through the through-hole, which is advantageous for impregnation of the electrode sheets with the electrolyte.

[0026] In some embodiments, the non-active material layer region has a plurality of through-holes spaced apart along the width direction of the first electrode sheet, which further reduces the rigidity of the current collector in the non-active material layer region and makes it easier to bend the first electrode sheet in the non-active material layer region.

[0027] In some embodiments, the grooves extend along the width of the first electrode sheet and penetrate the active material layer, making it easier to form the grooves and easier to bend the first electrode sheet in the groove regions.

[0028] In some embodiments, the active material layer has a plurality of grooves that are spaced apart along the width of the first electrode sheet, so that the first electrode sheet has good bending properties in the groove regions and sufficient strength in the groove regions, making it less susceptible to breakage.

[0029] In some embodiments, the folded segment includes a current collector and two active material layers, with the two active material layers disposed on opposite sides of the current collector, and the guide portion includes a through-hole disposed in the folded segment. The through-hole penetrates the current collector and the two active material layers, or the through-hole penetrates the current collector and the two active material layers cover the through-hole. The reduced rigidity of the folded segment in the area where the through-hole is disposed facilitates folding of the first electrode sheet at the through-hole position, forming a corresponding folded segment. When the through-hole penetrates the current collector and the two active material layers, the first electrode sheet has better bending performance in the through-hole area. Furthermore, in a battery cell, the electrolyte flows between the first and second electrode sheets through the through-hole, which is advantageous for impregnating the electrode sheets with the electrolyte. When the through-hole penetrates the current collector and the two active material layers cover the through-hole, the first electrode sheet has sufficient strength in the area where the through-hole is disposed, reducing the risk of breakage during the folding process. In addition, when forming the first electrode sheet, first, through holes are formed in the current collector, and then an active material layer is placed on the surface of the current collector, so that the active material layer covers the through holes, thereby reducing the difficulty of forming the first electrode sheet.

[0030] In some embodiments, the guide portion includes a plurality of through holes spaced apart along the width direction of the first electrode sheet, thereby further reducing the stiffness of the bending segment in the region where the through holes are provided, making the first electrode sheet more easily bendable in the region where the through holes are provided.

[0031] In some embodiments, the through-hole is a rectangular hole, which has a simple structure and is easy to form.

[0032] In some embodiments, the cross section of the through hole is rectangular, and the length direction of the rectangle coincides with the width direction of the first electrode sheet, thereby making the folding position of the first electrode sheet more accurate.

[0033] In some embodiments, the length of the rectangle is a and the width is b, and the ratio satisfies 10≦a / b≦400. If a / b<10, the dimensions of the through-holes in the folding direction of the folding segments are large, resulting in poor folding consistency of the first electrode sheet in the through-hole regions, which may affect the folding accuracy of the first electrode sheet. If a / b>400, the dimensions of the through-holes in the folding direction of the folding segments are small, resulting in poor guiding ability of the through-holes in the folding of the first electrode sheet, which may also affect the folding accuracy of the first electrode sheet. Therefore, when the ratio satisfies 10≦a / b≦400, the through-holes have an elongated structure extending along the width direction of the first electrode sheet, which improves the folding consistency of the first electrode sheet, making the folding position more accurate, and improving the folding efficiency of the first electrode sheet.

[0034] In some embodiments, 20≦a / b≦100. The folding efficiency of the first electrode sheet can be further improved.

[0035] In some embodiments, 3 mm≦a≦20 mm and / or 0.05 mm≦b≦0.3 mm.

[0036] In a second aspect, an embodiment of the present application provides a battery cell including a housing and an electrode assembly according to one embodiment described in the first aspect, wherein the electrode assembly is accommodated in the housing.

[0037] In a third aspect, an embodiment of the present application provides a battery including a battery cell according to any one of the embodiments described in the second aspect.

[0038] In a fourth aspect, an embodiment of the present application provides an electric device including a battery cell according to any one of the embodiments described in the second aspect, wherein the battery cell is used to provide electric energy. [Brief explanation of the drawings]

[0039] In order to more clearly explain the technical solutions of the embodiments of the present application, the drawings necessary for the embodiments of the present application will be briefly described below. It should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and those skilled in the art can obtain other related drawings based on these drawings without any creative efforts.

[0040] [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] FIG. 1 is an exploded view of a battery according to some embodiments of the present application. [Figure 3] FIG. 1 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] 1 is a structural schematic diagram of an electrode assembly according to some embodiments of the present application; [Figure 5] 10A to 10C are structural schematic diagrams of electrode assemblies according to some further embodiments of the present application. [Figure 6] 3A to 3C are structural schematic diagrams of electrode assemblies according to further embodiments of the present application. [Figure 7] 3A to 3C are structural schematic diagrams of electrode assemblies according to some other embodiments of the present application. [Figure 8] FIG. 1 is a perspective view of an electrode assembly according to some embodiments of the present application. [Figure 9] FIG. 9 is a perspective view of the structural unit shown in FIG. 8. [Figure 10] FIG. 10 is a structural schematic diagram of the structural unit shown in FIG. 9 after being unfolded. [Figure 11] FIG. 2 is a perspective view of a first electrode sheet according to some embodiments of the present application. [Figure 12] 1 is a structural schematic diagram of a first electrode sheet according to some embodiments of the present application. [Figure 13] FIG. 13 is a partial view of the first electrode sheet shown in FIG. 12 after being unfolded. [Figure 14] FIG. 14 is a plan view of the first electrode sheet shown in FIG. [Figure 15] 3A to 3C are structural schematic diagrams of first electrode sheets according to some further embodiments of the present application. [Figure 16] FIG. 16 is a partial view of the first electrode sheet shown in FIG. 15 after being unfolded. [Figure 17] 10A and 10B are partial views of the first electrode sheet after unfolding according to further embodiments of the present application. [Figure 18] FIG. 18 is a plan view of the first electrode sheet shown in FIG. [Figure 19] FIG. 2 is a plan view of a first electrode sheet after being unfolded according to some embodiments of the present application. [Figure 20] FIG. 10 is a plan view of a first electrode sheet according to further some embodiments of the present application after being unfolded. [Figure 21] FIG. 10 is a partial view of a first electrode sheet according to some other embodiments of the present application after being unfolded. [Figure 22] FIG. 22 is a plan view of the first electrode sheet shown in FIG. 21. [Figure 23] 10A and 10B are partial views of the first electrode sheet after unfolding according to further some embodiments of the present application. [Figure 24] FIG. 24 is a plan view of the current collector shown in FIG. 23. [Figure 25] FIG. 19 is a partial enlarged view of a portion A in FIG. [Figure 26] FIG. 23 is a partial enlarged view of a portion B in FIG. 22. DETAILED DESCRIPTION OF THE INVENTION

[0041] In order to clarify the objectives, technical solutions and advantages of the embodiments of the present application, the technical solutions of the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. It is clear that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. Based on the embodiments of the present application, any other embodiments that can be obtained by a person skilled in the art without any creative effort fall within the scope of protection of the present application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terms used in the specification of the application are merely for the purpose of describing specific embodiments and are not intended to limit the present application. The terms "comprise" and "have" and any variations thereof in the specification, claims, and drawings of the present application are intended to cover a non-exclusive "inclusion." The terms "first," "second," etc. in the specification, claims, or drawings of the present application are intended to distinguish between different objects and are not intended to describe a specific order or a subordinate relationship.

[0043] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described with reference to the embodiment is included in at least one embodiment of the present application. The appearances of such a term in various places in the present specification do not necessarily refer to the same embodiment, nor are they exclusive, independent, or alternative embodiments of other embodiments.

[0044] In the description of this application, unless otherwise clearly specified and limited, the terms "attach," "couple," "connect," and "mount" should be understood in a broad sense. For example, they may refer to a fixed connection, a detachable connection, an integral connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific circumstances.

[0045] The term "and / or" in this application is merely used to describe the relation between related objects, and indicates that three types of relations can exist. For example, A and / or B can indicate three situations: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects before and after it are in an "or" relationship.

[0046] In the embodiments of the present application, the same reference numerals denote the same elements, and detailed descriptions of the same elements will be omitted for the sake of brevity. It should be understood that the thickness, length, width, and other dimensions of the various elements in the embodiments of the present application, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and do not limit the present application in any way.

[0047] As used herein, "plurality" means two or more (including two).

[0048] In the embodiments of the present application, the battery cell may be a secondary battery, and a secondary battery refers to a battery cell that can be continuously used by activating the active material by charging after discharging the battery cell.

[0049] The battery cells may be lithium ion batteries, sodium ion batteries, lithium metal batteries, sodium metal batteries, lithium sulfur batteries, magnesium ion batteries, nickel metal hydride batteries, nickel cadmium batteries, lead acid batteries, etc., and examples of the present application are not limited thereto.

[0050] A battery cell generally includes an electrode assembly, which includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (e.g., lithium ions) travel back and forth between the positive and negative electrodes, absorbing and releasing them. The separator, located between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes and allows the active ions to pass through.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0052] For example, the positive electrode current collector has two surfaces facing each other in the thickness direction thereof, and the positive electrode active material is provided on one or both of the two facing surfaces of the positive electrode current collector.

[0053] For example, the positive electrode current collector can be a metal foil or a composite current collector. For example, the metal foil sheet can be silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbonized electrode, carbon, nickel, or titanium. The composite current collector can include a base layer of a polymer material and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0054] For example, the positive electrode active material may include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound thereof. However, the present application is not limited to these materials, and other materials used as battery positive electrode active materials may be used. These positive electrode active materials may be used alone or in combination of two or more. Here, examples of lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO), lithium nickel oxide (e.g., LiNiO), lithium manganese oxide (e.g., LiMnO, LiMnO), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 It can also be abbreviated as LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523 (can also be abbreviated as LiNi 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (can also be abbreviated as LiNi 0.6 Co 0.25 Mn 0.25 O2(NCM 211 (can also be abbreviated as LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (can also be abbreviated as LiN) i0.8 Co 0.1 Mn 0.1 O2(NCM 811 ), lithium nickel cobalt manganese oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 O2) and modified compounds thereof, etc.

[0055] In some embodiments, the positive electrode may be a metal foam. Examples of the metal foam include nickel foam, copper foam, aluminum foam, alloy foam, and carbon foam. When a metal foam is used as the positive electrode, the surface of the metal foam may not necessarily be provided with a positive electrode active material, but may also be provided with a positive electrode active material. For example, a lithium source material, such as potassium metal or sodium metal, may be filled and / or deposited within the metal foam, and the lithium source material may be lithium metal and / or a lithium-rich material.

[0056] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0057] For example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, the metal foil sheet can be silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbonized electrode, carbon, nickel, or titanium. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymer substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0058] For example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material provided on at least one surface of the negative electrode current collector.

[0059] For example, the negative electrode current collector has two surfaces facing each other in the thickness direction thereof, and the negative electrode active material is provided on one or both of the two facing surfaces of the negative electrode current collector.

[0060] For example, the negative electrode active material may be a negative electrode active material known in the art and used in battery cells. For example, 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, and lithium titanate. The silicon-based material may be at least one selected from elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be at least one selected from elemental tin, tin oxy compounds, and tin alloys. However, the present application is not limited to these materials, and other materials used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0061] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0062] In some embodiments, the separator is a separator film. The type of the separator film of the present application is not particularly limited, and any known porous separator film having good chemical stability and mechanical stability can be selected.

[0063] For example, the main material of the separator film may be at least one selected from glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator film may be a single-layer film or a multi-layer composite film, and is not particularly limited. When the separator film is a multi-layer composite film, the materials of each layer may be the same or different, and are not particularly limited. The separator may be a single member located between the positive electrode and the negative electrode, or may be attached to the surfaces of the positive electrode and the negative electrode.

[0064] In some embodiments, the separator is a solid electrolyte disposed between the positive and negative electrodes, which simultaneously transports ions and separates the positive and negative electrodes.

[0065] In some embodiments, the battery cell further includes an electrolyte, which serves to conduct ions between the positive electrode and the negative electrode. The type of electrolyte is not particularly limited in this application and can be selected according to needs. The electrolyte may be liquid, gel, or solid.

[0066] Here, the liquid electrolyte includes an electrolyte salt and a solvent.

[0067] In some embodiments, the electrolyte salt may be at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bisoxalate borate, lithium difluorobisoxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0068] In some embodiments, the solvent may be at least one selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene 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 be an ether-based solvent. The ether-based solvent 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, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0069] Here, the gel electrolyte contains a skeletal network with a polymer as an electrolyte, and is blended with an ionic liquid and a lithium salt.

[0070] Here, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0071] The polymer solid electrolyte may be, for example, polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0072] By way of example, the inorganic solid electrolyte may be one or more of oxide solid electrolytes (crystalline perovskites, sodium superionic conductors, garnets, amorphous LiPON films), sulfide solid electrolytes (crystalline lithium superionic conductors (lithium germanium phosphate sulfur, argyrodite), amorphous sulfides), and halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0073] Illustratively, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymeric solid electrolyte.

[0074] In some embodiments, the electrode assembly is a laminated sheet structure.

[0075] For example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0076] For example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with one positive electrode sheet sandwiched between adjacent folded segments.

[0077] Illustratively, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0078] For example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0079] Illustratively, the separator may be provided continuously, and may be provided between any adjacent positive or negative electrode sheets by folding or wrapping.

[0080] In some embodiments, the electrode assembly is provided with tabs that allow current to be conducted from the electrode assembly, including a positive electrode tab and a negative electrode tab.

[0081] In some embodiments, the battery cell may include a housing. The housing is used to seal components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), an aluminum-plastic film, or the like.

[0082] For example, the battery cells may be cylindrical battery cells, prismatic battery cells, soft-packaged battery cells, or other shaped battery cells, and prismatic battery cells include square-case battery cells, blade-shaped battery cells, and polygonal prism-shaped batteries, and polygonal prism-shaped batteries include, for example, hexagonal prism-shaped batteries, and are not particularly limited in this application.

[0083] A battery as referred to in the examples of this application refers to a single physical module that contains one or more battery cells and provides higher voltage and capacity.

[0084] In some embodiments, the battery may be a battery module, and if there are multiple battery cells, the multiple battery cells are fixed side by side to form a battery module.

[0085] In some embodiments, the battery may be a battery pack, which includes a housing and battery cells, and the battery cells or modules are housed in the housing.

[0086] In some embodiments, the housing may be part of a chassis structure of a vehicle, for example, a portion of the housing may form at least a portion of the floor of the vehicle, or a portion of the housing may form at least a portion of the transverse and longitudinal beams of the vehicle.

[0087] In some embodiments, the battery may be a power storage device, including a power storage collection container, a power storage cabinet, or the like.

[0088] In battery cells, electrode assemblies are generally divided into two types: stacked and wound. A typical stacked electrode assembly may include one first electrode sheet and multiple second electrode sheets, where the first and second electrode sheets have opposite polarities. The first electrode sheet is folded back and forth, and the straight segments formed after the first electrode sheet is folded are alternately arranged with the second electrode sheets. During the electrode assembly forming process, as the number of straight segments in the first electrode sheet increases, the electrode assembly is prone to tilting, causing the electrode sheets to misalign with each other and reducing the reliability of the electrode assembly.

[0089] In view of this, an embodiment of the present application provides an electrode assembly including a plurality of structural units, the plurality of structural units being stacked. The structural units include a first electrode sheet and a second electrode sheet having opposite polarities. The first electrode sheet includes a structural unit and a plurality of straight segments, with two adjacent straight segments being spaced apart along a first direction and connected to one structural unit. The second electrode sheets and the straight segments are alternately arranged along the stacking direction of the plurality of structural units.

[0090] In such an electrode assembly, the electrode assembly is divided into multiple structural units, and the number of layers of straight segments of the first electrode sheet in each structural unit is reduced, thereby reducing the risk of tilting of the structural units. During manufacturing, the structural units are first formed using the first electrode sheet and the second electrode sheet, and then multiple structural units can be stacked. This reduces the risk of tilting during the electrode assembly forming process, thereby reducing the risk of misalignment between the electrode sheets and effectively improving the reliability of the electrode assembly.

[0091] The electrode assemblies described in the embodiments of the present application are applicable to battery cells, batteries, and electrical devices that use battery cells.

[0092] The electric device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, an aerospace equipment, an electric toy, an electric tool, etc. The vehicle may be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle, and the new energy vehicle may be an electric vehicle (BEV), a hybrid vehicle, or a range-extender vehicle, etc. The aerospace equipment includes an airplane, a rocket, a space shuttle, a spaceship, etc. The electric toy includes a stationary or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting power tool, a polishing power tool, an assembly power tool, and a railway power tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact driver drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present application are not particularly limited to the electric device described above.

[0093] In the following embodiments, for convenience of explanation, the electrical device will be described as a vehicle.

[0094] Please refer to Fig. 1. Fig. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head, or tail of the vehicle 1000. The battery 100 may be used to supply power to the vehicle 1000, for example, the battery 100 may be used as a driving power source for the vehicle 1000.

[0095] The vehicle 1000 may further include a controller 200 and a motor 300, where the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the electrical needs of the vehicle 1000 for starting, navigation, and operation during driving.

[0096] In some embodiments of the present application, the battery 100 may not only serve as the operating power source for the vehicle 1000, but may also provide the driving power for the vehicle 1000 in place of or partially in place of fuel oil or natural gas.

[0097] Please refer to Figure 2. Figure 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20 housed within the battery cell 10.

[0098] Here, the housing 20 is a member that houses the battery cells 10, and the housing 20 provides a housing space for the battery cells 10. The housing 20 can have a variety of structures. In some embodiments, the housing 20 includes a first portion 201 and a second portion 202, which are covered with each other to define a housing space for housing the battery cells 10. The first portion 201 and the second portion 202 may have a variety of shapes, such as a rectangular parallelepiped or a cylinder. The first portion 201 may have a hollow structure with one side open, and the second portion 202 may also have a hollow structure with one side open. When the open side of the second portion 202 is covered with the open side of the first portion 201, the housing 20 having a housing space may be formed. The first part 201 may have a hollow structure with one side open, and the second part 202 may have a plate-like structure, and when the second part 202 is closed over the open side of the first part 201, a housing 20 having an accommodation space is formed. The first part 201 and the second part 202 may be sealed by a sealing element, which may be a seal ring, a sealant, or the like.

[0099] The battery 100 may have one or more battery cells 10. When there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, parallel, or multiple rows, and multiple rows means that the multiple battery cells 10 are not only connected in series but also in parallel. A battery module may be formed by connecting multiple battery cells 10 in series, parallel, or multiple rows, and the multiple battery modules may be further connected in series, parallel, or multiple rows to form a whole and housed in a housing 20. All of the battery cells 10 may be connected in direct, parallel, or multiple rows, and the whole made up of all the battery cells 10 may be housed in a housing 20.

[0100] Please refer to Figure 3. Figure 3 is an exploded view of a battery cell 10 according to some embodiments of the present application. The battery cell 10 includes a housing 1 and an electrode assembly 2, and the electrode assembly 2 is housed within the housing 1.

[0101] The housing 1 is a member for accommodating the electrode assembly 2, the electrolyte, etc. For example, the housing 1 may include a casing 11 and an end cover 12. The electrolyte may be an electrolytic solution.

[0102] The casing 11 may have a hollow structure with one end open, or may have a hollow structure with both opposing ends open. The casing 11 may have various shapes such as a cylindrical body or a rectangular parallelepiped. The casing 11 may be made of a variety of materials such as copper, iron, aluminum, steel, and aluminum alloy.

[0103] The end cover 12 is a member that seals the opening of the casing 11 to isolate the internal environment of the battery cell 10 from the external environment. Together with the casing 11, the end cover 12 defines an accommodation space for accommodating the electrode assembly 2, electrolyte, and other components. The end cover 12 can be connected to the casing 11 by welding or seaming to seal the opening of the casing 11. The shape of the end cover 12 can match the shape of the housing 1. For example, the casing 11 can have a rectangular parallelepiped structure and the end cover 12 can have a rectangular plate-like structure that matches the housing 1. Furthermore, for example, the casing 11 can have a cylindrical structure and the end cover 12 can have a circular plate-like structure that matches the casing 11. The end cover 12 can be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, and plastic. The end cover 12 and the casing 11 can be made of the same or different materials.

[0104] In an embodiment in which the casing 11 has an opening at one end, one end cover 12 may be provided correspondingly. In an embodiment in which the casing 11 has openings at opposite ends, two end covers 12 may be provided correspondingly, with the two end covers 12 sealing the two openings of the casing 11 respectively, and the two end covers 12, together with the casing 11, defining an accommodation space.

[0105] In some embodiments, the battery cell 10 further includes an electrode terminal, which is provided on the housing 1 and electrically connected to the tab of the electrode assembly 2 to output electrical energy from the battery cell 10. The electrode terminal may be provided on the casing 11 of the housing 1 or on the end cover 12 of the housing 1. The electrode terminal and the tab may be directly connected, for example, by direct welding. The electrode terminal and the tab may also be indirectly connected, for example, via a current collecting member. The current collecting member may be a metal conductor such as copper, iron, aluminum, steel, or an aluminum alloy.

[0106] 3, an opening is formed at one end of the casing 11, and the housing 1 has one end cover 12, which seals one opening of the casing 11. The end cover 12 is provided with two electrode terminals, which are a positive terminal 3 and a negative terminal 4, and a positive electrode tab 21 and a negative electrode tab 22 are formed at one end of the electrode assembly 2 facing the end cover 12, with the positive electrode terminal 3 electrically connected to the positive electrode tab 21 and the negative electrode terminal 4 electrically connected to the negative electrode tab 22.

[0107] Please refer to FIG. 4. FIG. 4 is a structural schematic diagram of an electrode assembly 2 according to some embodiments of the present application. According to a first aspect, the embodiments of the present application provide an electrode assembly 2, which includes a plurality of structural units 23 stacked along a first direction X, and each structural unit 23 includes a first electrode sheet 231 and a second electrode sheet 232. The first electrode sheet 231 includes a bent segment 2312 and a plurality of straight segments 2311, where two adjacent straight segments 2311 are spaced apart along the first direction X and are connected to one bent segment 2312. The second electrode sheet 232 has an opposite polarity to the first electrode sheet 231, and the second electrode sheet 232 and the straight segments 2311 are alternately arranged along the first direction X.

[0108] The number of structural units 23 in the electrode assembly 2 may be two, three, four, five or more. The first electrode sheet 231 and the second electrode sheet 232 in the structural unit 23 may be of opposite polarity, with the first electrode sheet 231 being the positive electrode sheet and the second electrode sheet 232 being the negative electrode sheet, or the first electrode sheet 231 being the negative electrode sheet and the second electrode sheet 232 being the positive electrode sheet. For example, the number of structural units 23 in the electrode assembly 2 is three or more.

[0109] Here, the first electrode sheet 231 has a folding structure. After the first electrode sheet 231 is folded, it forms a folded segment 2312 and a plurality of straight segments 2311. The straight segment 2311 is a straight portion of the first electrode sheet 231 that is not folded. The thickness direction of the straight segment 2311 coincides with the first direction X, and the plurality of straight segments 2311 of the first electrode sheet 231 are arranged along the first direction X. The number of straight segments 2311 in the first electrode sheet 231 may be two, three, four, five, or more. Of course, the number of straight segments 2311 in the first electrode sheet 231 may be an odd number or an even number. The number of straight segments 2311 in two adjacent structural units 23 may or may not be equal. The bent segment 2312 is a bent portion of the first electrode sheet 231, and is connected to two adjacent straight segments 2311. The bent segment 2312 is connected to the end of the straight segment 2311 along the second direction Y, which is perpendicular to the first direction X. The bent segment 2312 may be arc-shaped, and the bending direction W of the bent segment 2312 is the extension direction of the arc in which the bent segment 2312 is located. The first electrode sheet 231 may have one or more bent segments 2312. It can be understood that the number of straight segments 2311 in the first electrode sheet 231 is one more than the number of bent segments 2312, and that if the number of straight segments 2311 in the first electrode sheet 231 is odd, the number of bent segments 2312 in the first electrode sheet 231 is even, and if the number of straight segments 2311 in the first electrode sheet 231 is even, the number of bent segments 2312 in the first electrode sheet 231 is odd. In some embodiments, the number of straight segments 2311 in the first electrode sheet 231 is 2 to 20, and further, the number of straight segments 2311 in the first electrode sheet 231 is 3 to 9.This not only reduces the risk of the first electrode sheet 231 being tilted during the folding process, but also ensures that the first electrode sheet 231 in the structural unit 23 has excellent stability after being formed.

[0110] The second electrode sheet 232 may have a linear sheet-like structure, and the thickness direction of the second electrode sheet 232 coincides with the first direction X. In the structural unit 23, there may be one or more second electrode sheets 232, and the number of second electrode sheets 232 may be one more than the straight segments 2311 of the first electrode sheet 231, or the number of second electrode sheets 232 may be one less than the straight segments 2311 of the first electrode sheet 231, or the number of second electrode sheets 232 may be equal to the number of straight segments 2311 of the first electrode sheet 231. If there are multiple second electrode sheets 232 in the structural unit 23, the multiple second electrode sheets 232 are arranged along the first direction X.

[0111] In the structural unit 23, the second electrode sheets 232 and the straight segments 2311 are arranged alternately, and the number of second electrode sheets 232 in the structural unit 23 is equal to the number of straight segments 2311, and both are three. For example, the structural unit 23 may be arranged in the form of straight segment 2311-second electrode sheet 232-straight segment 2311-second electrode sheet 232-straight segment 2311-second electrode sheet 232.

[0112] Note that the alternating arrangement of the second electrode sheet 232 and the straight segments 2311 only indicates that the second electrode sheet 232 and the straight segments 2311 are arranged in an alternating array, and does not limit the possibility that no other components are provided between the second electrode sheet 232 and the straight segments 2311. Other components may be provided between the second electrode sheet 232 and the straight segments 2311. For example, the structural unit 23 further includes a separator film 233, and the second electrode sheet 232 and the first electrode sheet 231 are separated by the separator film 233 to achieve insulation and isolation between the second electrode sheet 232 and the first electrode sheet 231. In this case, the separator film 233 is provided between the second electrode sheet 232 and the straight segments 2311 of the first electrode sheet 231.

[0113] In the embodiment of the present application, dividing the electrode assembly 2 into a plurality of structural units 23 reduces the number of layers of the straight segments 2311 of the first electrode sheet 231 in the structural units 23, thereby reducing the risk of tilting of the structural units 23. During manufacturing, the structural units 23 are first formed using the first electrode sheet 231 and the second electrode sheet 232, and then a plurality of structural units 23 can be stacked. This reduces tilting during the formation process of the electrode assembly 2, thereby reducing the risk of misalignment between the electrode sheets and effectively improving the reliability of the electrode assembly 2.

[0114] In some embodiments, with continued reference to FIG. 4, the number of straight segments 2311 of the first electrode sheet 231 in at least one structural unit 23 is greater than two.

[0115] The number of straight segments 2311 in one structural unit 23 may be greater than two, and the number of straight segments 2311 in multiple structural units 23 may be greater than two. The number of straight segments 2311 in some structural units 23 may be greater than two, and the number of straight segments 2311 in all structural units 23 may be greater than two.

[0116] Taking the electrode assembly 2 as an example where there are three structural units 23, the number of straight segments 2311 in each of the three structural units 23 may be greater than two, or the number of straight segments 2311 in each of two structural units 23 may be greater than two, while the number of straight segments 2311 in each of the other structural units 23 may be two. As shown in FIG. 4 , the number of straight segments 2311 in each of the two structural units 23 may be two, while the number of straight segments 2311 in each of the other structural units 23 may be greater than two.

[0117] In this embodiment, the number of straight segments 2311 in at least one structural unit 23 is greater than two, which increases the number of straight segments 2311 in at least one structural unit 23 and effectively improves the manufacturing efficiency of the electrode assembly 2. For example, when cutting tabs for the first electrode sheet 231 in the structural unit 23, the number of straight segments 2311 in the first electrode sheet 231 is greater, so that more tabs can be cut at one time, thereby improving the manufacturing efficiency of the electrode assembly 2.

[0118] In some embodiments, with continued reference to FIG. 4, the number of straight segments 2311 of the first electrode sheet 231 in at least one structural unit 23 is an odd number.

[0119] In a structural unit 23 having an odd number of straight segments 2311, the number of straight segments 2311 may be three, five, seven or more.

[0120] The number of straight segments 2311 in one structural unit 23 may be odd, or the number of straight segments 2311 in multiple structural units 23 may be odd. The number of straight segments 2311 in some structural units 23 may be odd, or the number of straight segments 2311 in all structural units 23 may be odd.

[0121] Taking the electrode assembly 2 as an example where there are three structural units 23, the number of straight segments 2311 in the three structural units 23 may all be odd, or the number of straight segments 2311 in two structural units 23 may all be odd and the number of straight segments 2311 in the other structural unit 23 may all be even. As shown in FIG. 4 , the number of straight segments 2311 in two structural units 23 may all be even and the number of straight segments 2311 in the other structural unit 23 may all be odd.

[0122] When the number of straight segments 2311 in the first electrode sheet 231 is odd, the number of folded segments 2312 in the first electrode sheet 231 is even, and the number of folded segments 2312 on both sides of the structural unit 23 in the second direction Y is equal. When the first electrode sheet 231 is subjected to a force along the first direction X, both of the folded segments 2312 on both sides of the structural unit 23 can deform, improving the structural stability of the first electrode sheet 231 and reducing the difference in the amount of deformation on both sides of the structural unit 23. This makes it less likely that the structural unit 23 will tilt, reducing the risk of misalignment between the electrode sheets, and improving the reliability of the electrode assembly 2.

[0123] In some embodiments, please refer to Fig. 5. Fig. 5 is a structural schematic diagram of an electrode assembly 2 according to some further embodiments of the present application. The number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is greater than two.

[0124] In this embodiment, the number of straight segments 2311 in a structural unit 23 may be odd or even. The straight segments 2311 in two adjacent structural units 23 may or may not be equal.

[0125] In this embodiment, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is greater than two, so that there are more straight segments 2311 of the first electrode sheet 231 in each structural unit 23. When the dimension of the electrode assembly 2 along the first direction X is constant, this is advantageous for reducing the number of structural units 23 of the electrode assembly 2, and can further improve the manufacturing efficiency of the electrode assembly 2.

[0126] In some embodiments, with continued reference to FIG. 5, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is an odd number.

[0127] There may be three, five, seven or more straight segments 2311 in a structural unit 23. The straight segments 2311 in two adjacent structural units 23 may or may not be equal.

[0128] In this embodiment, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is odd, and thus the number of folded segments 2312 in each first electrode sheet 231 is even, and the number of folded segments 2312 on both sides of each structural unit 23 perpendicular to the first direction X (second direction Y) is equal. When the first electrode sheet 231 is subjected to a force along the first direction X, both of the folded segments 2312 on both sides of the structural unit 23 can deform. This reduces the difference in the amount of deformation on both sides of the structural unit 23, and therefore the first electrode sheet 231 in each structural unit 23 has excellent structural stability, further reducing the risk of the structural unit 23 tilting and reducing the risk of the electrode assembly 2 tilting.

[0129] In some embodiments, with continued reference to FIG. 5, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is three.

[0130] If there are too many straight segments 2311 in the structural unit 23, the risk of tilting increases during the folding process of the first electrode sheet 231. By providing three straight segments 2311 in each structural unit 23, not only is the risk of tilting during the folding process of the first electrode sheet 231 reduced, but the first electrode sheet 231 in the structural unit 23 has excellent stability after molding, reducing the risk of the electrode assembly 2 tilting.

[0131] In some embodiments, the number of straight segments 2311 of the first electrode sheet 231 in at least two structural units 23 is not equal.

[0132] It can be understood that the numbers of straight segments 2311 of the first electrode sheets 231 in n structural units 23 are unequal, and n≧2, and the numbers of straight segments 2311 of the first electrode sheets 231 in any two of the n structural units 23 are unequal. Taking n=3 as an example, where the numbers of straight segments 2311 of the first electrode sheets 231 in three structural units 23 are unequal, it can be understood that the numbers of straight segments 2311 of the first electrode sheets 231 in any two of the three structural units 23 are unequal, for example, one structural unit 23 has two straight segments 2311, another structural unit 23 has three straight segments 2311, and another structural unit 23 has four straight segments 2311.

[0133] In this embodiment, the types of structural units 23 in the electrode assembly 2 are diverse, and multiple structural units 23 adopt multiple combination forms to improve the versatility of the electrode assembly 2 and to better adapt to market needs.

[0134] In some embodiments, please refer to FIG. 6. FIG. 6 is a structural schematic diagram of an electrode assembly 2 according to some embodiments of the present application. The plurality of structural units 23 includes a first structural unit 23a, a second structural unit 23b, and a third structural unit 23c arranged in order along the first direction X. Here, the number of straight segments 2311 of the first electrode sheet 231 in the first structural unit 23a and the number of straight segments 2311 of the first electrode sheet 231 in the third structural unit 23c are both even numbers, and the number of straight segments 2311 of the first electrode sheet 231 in the second structural unit 23b is odd numbers.

[0135] The first structural unit 23a, the second structural unit 23b, and the third structural unit 23c are three adjacent structural units 23 among the plurality of structural units 23. The number of structural units 23 in the electrode assembly 2 may be three, and the three structural units 23 are respectively located at the first structural unit 23a, the second structural unit 23b, and the third structural unit 23c, or the number of structural units 23 in the electrode assembly 2 may be greater than three, and the three consecutively arranged structural units 23 are respectively the first structural unit 23a, the second structural unit 23b, and the third structural unit 23c.

[0136] The number of straight segments 2311 in the first structural unit 23a and the number of straight segments 2311 in the third structural unit 23c are both even, for example, 2, 4, 6, 8, or more. The number of straight segments 2311 in the first structural unit 23a and the number of straight segments 2311 in the third structural unit 23c may or may not be equal. The number of straight segments 2311 in the second structural unit 23b is odd, for example, 3, 5, 7, 9, or more.

[0137] 6, the number of straight segments 2311 in the first structural unit 23a and the number of straight segments 2311 in the third structural unit 23c are each two, while the number of straight segments 2311 in the second structural unit 23b is three. The first electrode sheet 231 in the first structural unit 23a and the first electrode sheet 231 in the third structural unit 23c form a substantially "U"-shaped structure, and the first electrode sheet 231 in the second structural unit 23b forms a substantially "S"-shaped structure.

[0138] In this embodiment, the second structural unit 23b, which is located in the middle, has an odd number of straight segments 2311, and the first structural unit 23a and the third structural unit 23c, which are located on both sides of the second structural unit 23b, have an even number of straight segments 2311. The number of bent segments 2312 on both sides of the second structural unit 23b perpendicular to the first direction X (second direction Y) is equal. When the combined structure formed by the first structural unit 23a, the second structural unit 23b, and the third structural unit 23c is subjected to a force along the first direction X, the difference in the amount of deformation of the combined structure on both sides perpendicular to the first direction X is small, so the combined structure has better structural stability and is less likely to tilt.

[0139] 4 to 6, in some embodiments, two straight segments 2311 located at both ends of the first electrode sheet 231 along the first direction X are the first straight segment 2311a and the second straight segment 2311b, respectively. In two adjacent structural units 23, the first straight segment 2311a in one structural unit 23 and the second straight segment 2311b in the other structural unit 23 are the two adjacent straight segments 2311. Along the second direction Y, one end of the first straight segment 2311a in one structural unit 23 away from the bent segment 2312 and one end of the second straight segment 2311b in the other structural unit 23 away from the bent segment 2312 are located on opposite sides of the electrode assembly 2, and the second direction Y is perpendicular to the first direction X.

[0140] The first direction X, the second direction Y and the width direction Z of the first electrode sheet are two-by-two and perpendicular to each other.

[0141] The first straight segment 2311a and the second straight segment 2311b are respectively the straight segments 2311 at both ends of the first electrode sheet 231 in the first direction X. When the first electrode sheet 231 has two straight segments 2311, it can be understood that the two straight segments 2311 are respectively the first straight segment 2311a and the second straight segment 2311b. It can be understood that, along the second direction Y, one end of the first straight segment 2311a in one structural unit 23 that is remote from the bent segment 2312 and one end of the second straight segment 2311b in another structural unit 23 that is remote from the bent segment 2312 are located on opposite sides of the electrode assembly 2, and that the bent segment 2312 connected to the first straight segment 2311a in one structural unit 23 and the bent segment 2312 connected to the second straight segment 2311b in the other structural unit 23 are respectively located on opposite sides of the electrode assembly 2.

[0142] In two adjacent structural units 23, a second electrode sheet 232 may be provided between the first straight segment 2311a in one structural unit 23 and the second straight segment 2311b in the other structural unit 23.

[0143] 6 as an example, the first structural unit 23a and the second structural unit 23b are two adjacent structural units 23, and along the second direction Y, one end of the first straight segment 2311a in the first structural unit 23a that is distant from the bent segment 2312 and one end of the second straight segment 2311b in the second structural unit 23b that is distant from the bent segment 2312 are located on opposite sides of the electrode assembly 2. Similarly, the second structural unit 23b and the third structural unit 23c are two adjacent structural units 23, and along the second direction Y, one end of the first straight segment 2311a in the second structural unit 23b that is distant from the bent segment 2312 and one end of the second straight segment 2311b in the third structural unit 23c that is distant from the bent segment 2312 are located on opposite sides of the electrode assembly 2.

[0144] In this embodiment, the two adjacent folded segments on each side of the electrode assembly 2 in the second direction Y are neither too far nor too close, and the layout is more reasonable, so that the electrode assembly 2 has better structural stability and further reduces the risk of tilting.

[0145] In some embodiments, with continued reference to FIGS. 4 to 6, in the structural unit 23, the number of straight segments 2311 of the first electrode sheet 231 is equal to the number of the second electrode sheets 232.

[0146] 6, the first structural unit 23a has two straight segments 2311 and two second electrode sheets 232, the second structural unit 23b has three straight segments 2311 and two second electrode sheets 232, and the third structural unit 23c has two straight segments 2311 and two second electrode sheets 232. This makes it possible to provide a second electrode sheet 232 between the first straight segment 2311a in the first structural unit 23a and the second straight segment 2311b in the second structural unit 23b, and a second electrode sheet 232 between the first straight segment 2311a in the second structural unit 23b and the second straight segment 2311b in the third structural unit 23c.

[0147] In this embodiment, the straight segments 2311 and the second electrode sheets 232 in the structural units 23 correspond to one another, thereby realizing an alternating arrangement of the straight segments 2311 and the second electrode sheets 232 in two adjacent structural units 23. As a result, in two adjacent structural units 23, the top electrode sheet of one structural unit 23 located at the bottom and the bottom electrode sheet of one structural unit 23 located at the top along the first direction X have opposite polarities. This makes full use of the straight segments 2311 and the second electrode sheets 232 of the two adjacent structural units 23, which is advantageous for improving the electrical capacity of the battery cell 10.

[0148] In some embodiments, please refer to Figure 7. Figure 7 is a structural schematic diagram of an electrode assembly 2 according to some other embodiments of the present application. The electrode assembly 2 further includes a third electrode sheet 234, which has the same polarity as the first electrode sheet 231. The third electrode sheet 234 is provided on at least one side of the multiple structural units 23 along the first direction X, and the third electrode sheet 234 is adjacent to the second electrode sheet 232 in the adjacent structural unit 23.

[0149] The third electrode sheet 234 may have a linear sheet-like structure, and the thickness direction of the third electrode sheet 234 coincides with the first direction X. Since the third electrode sheet 234 and the first electrode sheet 231 have the same polarity, the third electrode sheet 234 and the second electrode sheet 232 have opposite polarities. It should be understood that if the second electrode sheet 232 is a negative electrode sheet, the third electrode sheet 234 is a positive electrode sheet, and if the second electrode sheet 232 is a positive electrode sheet, the third electrode sheet 234 is a negative electrode sheet.

[0150] The electrode assembly 2 may have one or two third electrode sheets 234. When a third electrode sheet 234 is provided on only one side of the plurality of structural units 23 along the first direction X, the electrode assembly 2 has one third electrode sheet 234, and the third electrode sheet 234 is the single electrode sheet located outermost in the first direction X of the electrode assembly 2. When a third electrode sheet 234 is provided on each side of the plurality of structural units 23 along the first direction X, the electrode assembly 2 has two third electrode sheets 234, and all structural units 23 are located between the two third electrode sheets 234, and the two third electrode sheets 234 are the two outermost electrode sheets in the first direction X of the electrode assembly 2.

[0151] The third electrode sheet 234 being adjacent to the second electrode sheet 232 in the adjacent structural unit 23 means that the third electrode sheet 234 and the second electrode sheet 232 in the adjacent structural unit 23 are adjacent electrode sheets, but this does not limit the absence of any other member between them. The third electrode sheet 234 and the adjacent second electrode sheet 232 may be separated by a separator film 233. The second electrode sheet 232 adjacent to the third electrode sheet 234 is the second electrode sheet 232 located outermost among the structural units 23 located at the end of the electrode assembly 2 along the first direction X.

[0152] In this embodiment, the outermost second electrode sheet 232 of the structural unit 23 located at the end of the electrode assembly 2 is fully utilized, and the outermost second electrode sheet 232 and the third electrode sheet 234 of the structural unit 23 located at the end of the electrode assembly 2 can transport metal ions during the charging and discharging process of the battery cell 10, which is advantageous for improving the electrical capacity of the battery cell 10.

[0153] In some embodiments, see FIGS. 4 to 7. The first electrode sheet 231 is a negative electrode sheet, and the second electrode sheet 232 is a positive electrode sheet. This makes it easier for the negative electrode sheet to cover the positive electrode sheet, reducing the risk of the positive electrode sheet protruding from the negative electrode sheet and improving the reliability of the electrode assembly 2. For example, if the battery cell 10 is a lithium-ion battery 100, having the negative electrode sheet cover the positive electrode sheet reduces the risk of lithium precipitation and further improves the reliability of the electrode assembly 2.

[0154] In some embodiments, please refer to Figures 8 and 9. Figure 8 is a perspective view of an electrode assembly 2 according to some embodiments of the present application, and Figure 9 is a perspective view of the structural unit 23 shown in Figure 8. Each straight segment 2311 is provided with a first tab 2313, and the multiple first tabs 2313 in each structural unit 23 are aligned along the first direction X, and / or each second electrode sheet 232 is provided with a second tab 2321, and each structural unit 23 includes multiple second electrode sheets 232, and the multiple second tabs 2321 in each structural unit 23 are aligned along the first direction X.

[0155] When the multiple first tabs 2313 in each structural unit 23 are aligned along the first direction X, the first tabs 2313 in two adjacent structural units 23 are also aligned along the first direction X, and the first tabs 2313 in the multiple structural units 23 are connected to form a first tab portion. When the multiple second tabs 2321 in each structural unit 23 are aligned along the first direction X, the second tabs 2321 in two adjacent structural units 23 are also aligned along the first direction X, and the second tabs 2321 in the multiple structural units 23 are connected to form a second tab portion. Here, one of the first tab portion and the second tab portion forms the positive electrode tab 21 of the electrode assembly 2, and the other forms the negative electrode tab 22 of the electrode assembly 2.

[0156] When the multiple first tabs 2313 in the structural unit 23 are aligned along the first direction X, busbar connection becomes easy, the entire structural unit 23 can be cut when cutting the first tabs 2313, and cutting efficiency of the first tabs 2313 can be improved, thereby improving manufacturing efficiency. When the multiple second tabs 2321 in the structural unit 23 are aligned along the first direction X, busbar connection becomes easy, the entire structural unit 23 can be cut when cutting the second tabs 2321, and cutting efficiency of the second tabs 2321 can be improved, thereby improving manufacturing efficiency.

[0157] For some embodiments, please continue to refer to Figures 9 and 10. Figure 10 is a structural schematic diagram of the structural unit 23 shown in Figure 9 after it has been unfolded. The structural unit 23 further includes a separator film 233, and the first electrode sheet 231 and the second electrode sheet 232 are both combined with the separator film 233, and the separator film 233 is arranged to separate the first electrode sheet 231 and the second electrode sheet 232.

[0158] Separator films 233 may be provided on both sides of the first electrode sheet 231 to separate the first electrode sheet 231 from the second electrode sheets 232 on both sides. By combining the separator films 233 and the first electrode sheet 231, the separator films 233 and the first electrode sheet 231 are fixed together. By combining the second electrode sheet 232 and the separator film 233, the second electrode sheet 232 and the separator film 233 are fixed together. The first electrode sheet 231 and the second electrode sheet 232 may be combined with the separator film 233 in a plurality of forms; for example, the first electrode sheet 231 and the second electrode sheet 232 are both connected to the separator film 233 by adhesive or hot melt.

[0159] When forming the structural unit 23, separator films 233 are compounded on both sides of the first electrode sheet 231, and then the second electrode sheets 232 are alternately compounded with the separator films 233 on both sides of the first electrode sheet 231. The first electrode sheet 231 is then repeatedly folded, finally achieving an alternating arrangement of the straight segments 2311 of the first electrode sheet 231 and the second electrode sheet 232, thereby enabling the structural unit 23 to be formed efficiently and quickly.

[0160] The separator film 233 provides insulation and separation between the first electrode sheet 231 and the second electrode sheet 232, reducing the risk of an internal short circuit in the electrode assembly 2. By combining the first electrode sheet 231 and the second electrode sheet 232 with the separator film 233, the first electrode sheet 231, the second electrode sheet 232, and the separator film 233 in the structural unit 23 have good integrity, and the risk of misalignment between the first electrode sheet 231 and the second electrode sheet 232 is unlikely to occur.

[0161] In some embodiments, please refer to Fig. 11. Fig. 11 is a perspective view of a first electrode sheet 231 according to some embodiments of the present application. The bending segment 2312 is provided with a guide portion 23121 that guides the bending of the bending segment 2312.

[0162] The guide portion 23121 is a structure that guides the bending of the bending segment 2312, and is used to fold the first electrode sheet 231 at a predetermined position to form the bending segment 2312. The guide portion 23121 may be a structure such as a groove or hole provided in the bending segment 2312, as long as it can guide the first electrode sheet 231 so that it can be folded at a predetermined position during the folding process to form the bending segment 2312. The guide portion 23121 may be located at an intermediate position of the bending segment 2312 along the bending direction W of the bending segment 2312.

[0163] The guide portion 23121 allows the first electrode sheet 231 to be folded at a predetermined position, improving the folding efficiency of the first electrode sheet 231, making the folding position more consistent, and making the relative position between the straight segment 2311 and the second electrode sheet 232 more accurate, thereby ensuring the reliability of the electrode assembly 2.

[0164] In some embodiments, with continued reference to FIG. 11, the guide portion 23121 includes a recessed groove 23122 provided in the bent segment 2312 .

[0165] The guide portion 23121 may have one or more grooves 23122. If the guide portion 23121 has one groove 23122, the groove 23122 may extend along the width direction Z of the first electrode sheet. If the guide portion 23121 has multiple grooves 23122, the multiple grooves 23122 may be arranged at intervals along the width direction Z of the first electrode sheet. Here, the width direction Z, the first direction X, and the second direction Y of the first electrode sheet are each two in number and perpendicular to each other.

[0166] In this embodiment, the folded segments 2312 are thinner in the areas where the grooves 23122 are provided, and the grooves 23122 have an excellent guiding effect, making it easier for the first electrode sheet 231 to bend at the positions of the grooves 23122 to correspond to the formed folded segments 2312. Such guide portions 23121 have a simple structure and are easy to form. At the same time, the arrangement of the grooves 23122 can alleviate the problem of lithium deposition at the folded portions of the first electrode sheet 231, thereby improving the service life of the electrode assembly 2.

[0167] In some embodiments, please refer to Figures 12 to 16. Figure 12 is a structural schematic diagram of a first electrode sheet 231 according to some embodiments of the present application, Figure 13 is a partial view of the first electrode sheet 231 shown in Figure 12 after being unfolded, Figure 14 is a plan view of the first electrode sheet 231 shown in Figure 13, Figure 15 is a structural schematic diagram of a first electrode sheet 231 according to some other embodiments of the present application, and Figure 16 is a partial view of the first electrode sheet 231 shown in Figure 15 after being unfolded. The folded segment 2312 includes a current collector 23123 and two active material layers 23124, the two active material layers 23124 being provided on both sides of the current collector 23123, and at least one active material layer 23124 is provided with a groove 23122.

[0168] The groove 23122 may be provided in one active material layer 23124, or the groove 23122 may be provided in two active material layers 23124. The depth of the groove 23122 may be smaller than the thickness of the active material layer 23124, or the depth of the groove 23122 may be equal to the thickness of the active material layer 23124.

[0169] In this embodiment, the grooves 23122 are formed in at least one active material layer 23124 of the bent segment 2312, thereby making it possible to thin a portion of the bent segment 2312, and this can be achieved in a simple manner.

[0170] In some embodiments, with continued reference to FIGS. 12 to 14, one active material layer 23124 is provided with a recessed groove 23122 .

[0171] In the folded segment 2312, the groove 23122 may be provided in one active material layer 23124 located inside the current collector 23123, or may be provided in one active material layer 23124 located outside the current collector 23123. For example, if the folded segment 2312 has an arc shape, the radius of one active material layer 23124 located outside the current collector 23123 is larger than the radius of one active material layer 23124 located inside the current collector 23123. For example, in the embodiment shown in FIGS. 12 to 14 , the groove 23122 extends along the width direction Z of the first electrode sheet and penetrates the active material layer 23124.

[0172] In this embodiment, the grooves 23122 are formed in only one active material layer 23124, which reduces the difficulty of forming the first electrode sheet 231. Specifically, when the grooves 23122 are formed in only one active material layer 23124 and the first electrode sheet 231 is folded two or more times, some of the grooves 23122 are located inside the folded segments 2312 and some of the grooves 23122 are located outside the folded segments 2312, thereby reducing the difficulty of forming and effectively controlling the problem of lithium deposition in the first electrode sheet 231. Furthermore, when the grooves 23122 are formed in only one active material layer 23124, the first electrode sheet 231 has a lower process difficulty of cutting grooves on one side and a simpler operation than when all of the grooves 23122 are located on the same side of the first electrode sheet 231 during unfolding, which requires positioning and alignment of the grooves 23122 on both sides.

[0173] In some embodiments, with continued reference to FIGS. 15 and 16, both of the two active material layers 23124 are provided with recessed grooves 23122 .

[0174] The grooves 23122 in the two active material layers 23124 are provided corresponding to each other. For example, the folded segment 2312 has an arc shape, and the grooves 23122 in the two active material layers 23124 are located in the same radial direction of the folded segment 2312, and the grooves 23122 in the two active material layers 23124 are located on both sides of the current collector 23123 along the radial direction of the folded segment 2312. Here, the grooves 23122 extend along the width direction Z of the first electrode sheet and penetrate the active material layers 23124.

[0175] In an embodiment in which the depth of the groove 23122 is equal to the thickness of the active material layer 23124, the two active material layers 23124 each have a groove 23122, so that the current collector 23123 is not covered by the active material layer 23124 in the area where the groove 23122 is provided, and this area is exposed, becoming the non-active material layer area 23125 of the current collector 23123.

[0176] In this embodiment, the active material layers 23124 on both sides of the current collector 23123 are provided with grooves 23122, so that the folded segment 2312 is thinner in the areas where the grooves 23122 are provided, making it easier to fold. At the same time, the problem of lithium deposition on the first electrode sheet 231 can be effectively alleviated.

[0177] In some embodiments, please refer to Fig. 17. Fig. 17 is a partial view of a first electrode sheet 231 according to some further embodiments of the present application after being unfolded. The guide portion 23121 further includes a through-hole 23126 penetrating the current collector 23123, and the region of the current collector 23123 corresponding to the groove 23122 forms a non-active material layer region 23125, and the through-hole 23126 is provided in the non-active material layer region 23125.

[0178] In this embodiment, the depth of the groove 23122 is equal to the thickness of the active material layer 23124, so that the current collector 23123 is not covered by the active material layer 23124 in the area where the groove 23122 is provided, forming a corresponding non-active material layer area 23125.

[0179] The number of through-holes 23126 provided in the non-active material layer region 23125 may be one or more. The through-holes 23126 may have a variety of shapes, such as a circle or a rectangle. The through-holes 23126 may be provided at a middle position of the non-active material layer 23124 in the width direction of the non-active material layer 23124. Here, the width direction of the non-active material layer 23124 is perpendicular to the width direction Z of the first electrode sheet and the thickness direction of the current collector 23123.

[0180] In this embodiment, the arrangement of the through-holes 23126 reduces the rigidity of the inactive material layer region 23125 of the current collector 23123. This reduces the rigidity of the inactive material layer region 23125, reinforcing the folding effect and further improving the folding efficiency of the first electrode sheet 231. Furthermore, in the battery cell 10, the electrolyte flows between the first electrode sheet 231 and the second electrode sheet 232 through the through-holes 23126, which is advantageous for impregnation of the electrode sheets with the electrolyte. This also effectively alleviates the problem of lithium deposition on the first electrode sheet 231.

[0181] In some embodiments, please refer to Figure 18. Figure 18 is a plan view of the first electrode sheet 231 shown in Figure 17. A plurality of through holes 23126 are provided in the non-active material layer region 23125, and the plurality of through holes 23126 are arranged at intervals along the width direction Z of the first electrode sheet.

[0182] The number of through-holes 23126 in the non-active material layer region 23125 may be two, three, four, five or more.

[0183] In this embodiment, the non-active material layer region 23125 is provided with a plurality of through holes 23126 arranged along the width direction Z of the first electrode sheet, which further reduces the rigidity of the current collector 23123 in the non-active material layer region 23125 and makes it easier for the first electrode sheet 231 to bend in the non-active material layer region 23125.

[0184] In some embodiments, with continued reference to FIGS. 14 and 18, the recessed grooves 23122 extend along the width direction Z of the first electrode sheet and penetrate the active material layer 23124.

[0185] It can be seen that both ends of the recessed groove 23122 extend to both ends of the active material layer 23124 along the width direction Z of the first electrode sheet.

[0186] Regardless of whether the grooves 23122 are provided in only the active material layer 23124 on one side of the current collector 23123 or in both of the active material layers 23124 on both sides of the current collector 23123, the grooves 23122 may all extend along the first direction X and penetrate the active material layer 23124.

[0187] In this embodiment, the grooves 23122 are easier to form, and the first electrode sheet 231 is easier to bend in the region of the grooves 23122.

[0188] In some embodiments, please refer to Figures 19 and 20. Figure 19 is a plan view of a first electrode sheet 231 according to some embodiments of the present application after being unfolded, and Figure 20 is a plan view of a first electrode sheet 231 according to other embodiments of the present application after being unfolded. The active material layer 23124 is provided with a plurality of grooves 23122, and the plurality of grooves 23122 are arranged at intervals along the width direction Z of the first electrode sheet.

[0189] The number of grooves 23122 provided in active material layer 23124 may be two, three, four, five or more. In an embodiment in which groove 23122 is provided in one active material layer 23124 located on only one side of current collector 23123, it can be understood that multiple grooves 23122 are provided in active material layer 23124 of that layer, and in an embodiment in which grooves 23122 are provided in two active material layers 23124 located on both sides of current collector 23123, each active material layer 23124 has multiple grooves 23122.

[0190] 19, the region of current collector 23123 corresponding to groove 23122 forms non-active material layer region 23125 (not shown in FIG. 19), and non-active material layer region 23125 is not provided with through-hole 23126. In the example shown in FIG. 20, the region of current collector 23123 corresponding to groove 23122 forms non-active material layer region 23125 (not shown in FIG. 20), and non-active material layer region 23125 is provided with through-hole 23126.

[0191] In this embodiment, the active material layer 23124 is provided with a plurality of grooves 23122 spaced apart along the width direction Z of the first electrode sheet, and the first electrode sheet 231 has good bending performance in the region of the plurality of grooves 23122, and the first electrode sheet 231 has sufficient strength in this region, making it less likely to break.

[0192] 21 to 24, in some embodiments, Fig. 21 is a partial view of first electrode sheet 231 according to some other embodiments of the present application after being unfolded, Fig. 22 is a plan view of first electrode sheet 231 shown in Fig. 21, Fig. 23 is a partial view of first electrode sheet 231 according to still another embodiment of the present application after being unfolded, and Fig. 24 is a plan view of current collector 23123 shown in Fig. 23. Bent segment 2312 includes current collector 23123 and two active material layers 23124, and two active material layers 23124 are respectively provided on both sides of current collector 23123, and guide portion 23121 includes through-holes 23126 provided in bent segment 2312. The through-holes 23126 pass through the current collector 23123 and the two active material layers 23124 , or the through-holes 23126 pass through the current collector 23123 , and the two active material layers 23124 cover the through-holes 23126 .

[0193] The number of through-holes 23126 provided in the bent segment 2312 may be one or more. The through-holes 23126 may have a variety of shapes such as a circle or a rectangle.

[0194] 21 and 22, through-hole 23126 penetrates current collector 23123 and two active material layers 23124. In the example shown in Figures 23 and 24, through-hole 23126 is provided in current collector 23123, through-hole 23126 penetrates current collector 23123, and both of two active material layers 23124 cover through-hole 23126.

[0195] In this embodiment, the rigidity of the region of the folding segment 2312 where the through-hole 23126 is provided is reduced, making the first electrode sheet 231 easier to fold at the position of the through-hole 23126, thereby forming the corresponding folding segment 2312. When the through-hole 23126 penetrates the current collector 23123 and the two active material layers 23124, the folding performance of the first electrode sheet 231 is improved in the region where the through-hole 23126 is provided. Furthermore, in the battery cell 10, the electrolyte flows between the first electrode sheet 231 and the second electrode sheet 232 through the through-hole 23126, which is advantageous for impregnation of the electrode sheets with the electrolyte. When the through-holes 23126 penetrate the current collector 23123 and the two active material layers 23124 cover the through-holes 23126, the first electrode sheet 231 has sufficient strength in the area where the through-holes 23126 are provided, and there is little risk of the first electrode sheet 231 breaking during the process of bending the first electrode sheet 231. Furthermore, when forming the first electrode sheet 231, first the through-holes 23126 are formed in the current collector 23123, and then the active material layers 23124 are disposed on the surface of the current collector 23123, so that the active material layers 23124 cover the through-holes 23126, thereby making it easier to form the first electrode sheet 231.

[0196] In some embodiments, with continued reference to Figures 22 and 24, the guide portion 23121 includes a plurality of through holes 23126, which are spaced apart along the width direction Z of the first electrode sheet.

[0197] The number of through holes 23126 in the bent segment 2312 may be two, three, four, five or more.

[0198] In this embodiment, the bending segment 2312 is provided with a plurality of through holes 23126 arranged along the width direction Z of the first electrode sheet, which further reduces the rigidity of the area of ​​the bending segment 2312 where the through holes 23126 are provided, making the first electrode sheet 231 easier to bend in the area where the through holes 23126 are provided.

[0199] In some embodiments, the through holes 23126 are rectangular holes.

[0200] The cross section of the through hole 23126 is rectangular, the cross section of the through hole 23126 is perpendicular to the axial direction of the through hole 23126 , and the axial direction of the through hole 23126 coincides with the thickness direction of the bent segment 2312 .

[0201] In this embodiment, the through-hole 23126 is a rectangular hole, and such a through-hole 23126 has a simple structure and is easy to form.

[0202] In some embodiments, as shown in FIGS. 18, 20, 22 and 24, the cross section of the through-hole 23126 is rectangular, and the length direction of the rectangle coincides with the width direction Z of the first electrode sheet.

[0203] The length direction of the rectangle is the length direction of the through-hole 23126, and the long side of the rectangle is longer than the short side.

[0204] In this embodiment, the length direction of the through holes 23126 coincides with the width direction Z of the first electrode sheet, so that the folding position of the first electrode sheet 231 can be more accurate.

[0205] In some embodiments, see Figures 25 and 26. Figure 25 is a partial enlarged view of part A in Figure 18, and Figure 26 is a partial enlarged view of part B in Figure 22. The length of the rectangle is a and the width is b, and 10≦a / b≦400 is satisfied.

[0206] a / b may be any point value of 10, 20, 40, 80, 100, 150, 180, 200, 250, 280, 300, 350, 380, 400 or any range value therebetween.

[0207] If a / b<10, the dimensions of the through holes 23126 in the folding direction W of the folding segments 2312 are large, and the folding consistency of the first electrode sheet 231 in the area of ​​the through holes 23126 is poor, which may affect the folding accuracy of the first electrode sheet 231. If a / b>400, the dimensions of the through holes 23126 in the folding direction W of the folding segments 2312 are small, and the through holes 23126 have a weak ability to guide the folding of the first electrode sheet 231, which may also affect the folding accuracy of the first electrode sheet 231. Therefore, when 10≦a / b≦400, the through holes 23126 have an elongated structure extending along the width direction Z of the first electrode sheet 231, which improves the consistency of the folding position of the first electrode sheet 231, makes the folding position of the first electrode sheet 231 more accurate, and improves the folding efficiency of the first electrode sheet 231.

[0208] In some embodiments, 20≦a / b≦100.

[0209] a / b may be any point value of 20, 30, 40, 50, 60, 70, 80, 90, 100 or any range value between the two.

[0210] In this embodiment, by satisfying 20≦a / b≦100, the folding efficiency of the first electrode sheet 231 can be further improved.

[0211] In some embodiments, 3 mm≦a≦20 mm and / or 0.05 mm≦b≦0.3 mm.

[0212] a may be any point value of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm or any range value between them.

[0213] b may be any point value of 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm or any range value therebetween.

[0214] An embodiment of the present application is a battery cell 10 including a housing 1 and an electrode assembly 2 according to any of the above-described embodiments, where the electrode assembly 2 provides the battery cell 10 housed within the housing 1.

[0215] An embodiment of the present application provides a battery 100 including a battery cell 10 according to any of the above-described embodiments.

[0216] An embodiment of the present application provides an electric device including a battery cell 10 according to any of the above-described embodiments for providing electric energy.

[0217] An embodiment of the present application further provides an electrode assembly 2 including a plurality of structural units 23, the plurality of structural units 23 being stacked along a first direction X, the structural units 23 including a first electrode sheet 231, a second electrode sheet 232, and a separator film 233, the separator films 233 being combined on both sides of the first electrode sheet 231, the second electrode sheet 232 being combined with the separator film 233, and the separator film 233 being arranged to separate the first electrode sheet 231 and the second electrode sheet 232. The first electrode sheet 231 has a folded structure, and includes a folded segment 2312 and a plurality of straight segments 2311, two adjacent straight segments 2311 being spaced apart along the first direction X and connected to one folded segment 2312. The first electrode sheet 231 is a negative electrode sheet, and the second electrode sheet 232 is a positive electrode sheet, and the second electrode sheets 232 and straight segments 2311 are alternately arranged along the first direction X. In the structural unit 23, the number of straight segments 2311 of the first electrode sheet 231 is equal to the number of the second electrode sheets 232.

[0218] Here, the number of straight segments 2311 of the first electrode sheet 231 in at least one structural unit 23 is odd, and the numbers of straight segments 2311 of the first electrode sheet 231 in at least two structural units 23 are unequal.

[0219] The bending segment 2312 is provided with a groove 23122, which is arranged to guide the bending of the bending segment 2312. The bending segment 2312 includes a current collector 23123 and two active material layers 23124, each of which is provided on either side of the current collector 23123. Each of the two active material layers 23124 is provided with a groove 23122, and the region of the current collector 23123 corresponding to the groove 23122 forms an inactive material layer region 23125. The inactive material layer region 23125 is provided with a plurality of through holes 23126, which are spaced apart along the width direction Z of the first electrode sheet. The cross section of the through hole 23126 is rectangular, and the length direction of the rectangle coincides with the width direction Z of the first electrode sheet. The length of the rectangle is a and the width is b, and the following conditions are satisfied: 10≦a / b≦400, 3 mm≦a≦20 mm, and 0.05 mm≦b≦0.3 mm.

[0220] In the above embodiment, dividing the electrode assembly 2 into multiple structural units 23 reduces the number of layers of straight segments 2311 of the first electrode sheet 231 in each structural unit 23, thereby reducing the risk of tilting of the structural units 23. This reduces the risk of tilting after multiple structural units 23 are stacked, thereby reducing the risk of misalignment between the electrode sheets and effectively improving the reliability of the electrode assembly 2. By having an odd number of straight segments 2311 in the first electrode sheet 231 in at least one structural unit 23, the number of bent segments 2312 on both sides of the structural unit 23 in the second direction Y is equal. When the first electrode sheet 231 is subjected to a force along the first direction X, both bent segments 2312 on both sides of the structural unit 23 are deformable. This improves the structural stability of the first electrode sheet 231, makes the structural units 23 less likely to tilt, reduces the risk of misalignment between the electrode sheets, and improves the reliability of the electrode assembly 2. The number of straight segments 2311 of the first electrode sheet 231 in at least two structural units 23 is unequal, which results in a variety of types of structural units 23 in the electrode assembly 2, and allows the structural units 23 to adopt multiple combinations to improve the versatility of the electrode assembly 2 and better meet market needs. In addition, the two active material layers 23124 of the folding segment 2312 are both provided with grooves 23122, which makes it easier for the first electrode sheet 231 to bend at the positions of the grooves 23122 and can guide the folding of the first electrode sheet 231, thereby improving the folding efficiency of the first electrode sheet 231 and increasing the consistency of the folding position. Since multiple through holes 23126 are arranged at intervals in the non-active material layer region 23125 of the current collector 23123, the rigidity of the current collector 23123 in the non-active material layer region 23125 can be effectively reduced, so that the first electrode sheet 231 can be more easily bent in the non-active material layer region 23125 and the problem of lithium deposition in the first electrode sheet 231 can be effectively improved.Furthermore, the cross section of the through hole 23126 is rectangular, the length direction of the rectangle coincides with the width direction Z of the first electrode sheet, and the length a and width b of the rectangle satisfy 10≦a / b≦400, so that the through hole 23126 has an elongated structure extending along the width direction Z of the first electrode sheet, which improves the consistency of the folding position of the first electrode sheet 231, makes the folding position of the first electrode sheet 231 more accurate, and improves the folding efficiency of the first electrode sheet 231.

[0221] It should be noted that, unless a contradiction arises, the embodiments and features of the embodiments in the present application can be combined with each other.

[0222] The above examples are merely for the purpose of illustrating the technical solution of the present application, and are not intended to limit the present application. Those skilled in the art can make various modifications and variations to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the concept and principles of the present application shall fall within the scope of the present application. [Explanation of symbols]

[0223] 1: housing, 11: casing, 12: end cover, 2: electrode assembly, 21: positive electrode tab, 22: negative electrode tab, 23: structural unit, 23a: first structural unit, 23b: second structural unit, 23c: third structural unit, 231: first electrode sheet, 2311: straight segment, 2311a: first straight segment, 2311b: second straight segment, 2312: bent segment, 23121: guide portion, 23122: groove, 23123: current collector , 23124: active material layer, 23125: inactive material layer region, 23126: through-hole, 2313: first tab, 232: second electrode sheet, 2321: second tab, 233: separator film, 234: third electrode sheet, 3: positive electrode terminal, 4: negative electrode terminal, 10: battery cell, 20: housing, 201: first part, 202: second part, 100: battery, 200: controller, 300: motor, 1000: vehicle, W: bending direction, X: first direction, Y: second direction, Z: width direction of first electrode sheet

Claims

1. a plurality of structural units stacked and arranged along a first direction; The structural unit is a first electrode sheet including a bent segment and a plurality of straight segments, wherein two adjacent straight segments are spaced apart along a first direction and connected to one of the bent segments; second electrode sheets having an opposite polarity to the first electrode sheets and arranged alternately with the straight segments along the first direction; Electrode assembly.

2. The number of the straight segments of the first electrode sheet in at least one of the structural units is greater than two; The electrode assembly of claim 1 .

3. The number of the straight segments of the first electrode sheet in at least one of the structural units is odd.

3. The electrode assembly according to claim 1 or 2.

4. the number of the straight segments of the first electrode sheet in each structural unit is greater than two; The electrode assembly according to any one of claims 1 to 3.

5. the number of the straight segments of the first electrode sheet in each of the structural units is odd; The electrode assembly according to any one of claims 1 to 4.

6. The number of the straight segments of the first electrode sheet in each structural unit is three.

6. The electrode assembly according to claim 4 or 5.

7. the number of straight segments of the first electrode sheet in at least two of the structural units is not equal; The electrode assembly according to any one of claims 1 to 3.

8. the plurality of structural units include a first structural unit, a second structural unit, and a third structural unit sequentially arranged along the first direction; the number of the straight segments of the first electrode sheet in the first structural unit and the number of the straight segments of the first electrode sheet in the third structural unit are both even numbers, and the number of the straight segments of the first electrode sheet in the second structural unit is odd numbers; The electrode assembly according to any one of claims 1 to 3 and 7.

9. the two straight segments located at both ends of the first electrode sheet along the first direction are a first straight segment and a second straight segment, respectively; Among two adjacent structural units, the first straight segment in one structural unit and the second straight segment in the other structural unit are two adjacent straight segments, and along a second direction, one end of the first straight segment in one structural unit that is away from the bent segment and one end of the second straight segment in the other structural unit that is away from the bent segment are located on opposite sides of the electrode assembly, respectively, and the second direction is perpendicular to the first direction. The electrode assembly according to any one of claims 1 to 8.

10. In the structural unit, the number of the straight segments of the first electrode sheet is equal to the number of the second electrode sheets; The electrode assembly according to any one of claims 1 to 9.

11. the electrode assembly further includes a third electrode sheet having the same polarity as the first electrode sheet, The third electrode sheet is provided on at least one side of the plurality of structural units along the first direction, and the third electrode sheet is adjacent to the second electrode sheet in the adjacent structural unit. The electrode assembly according to any one of claims 1 to 10.

12. The first electrode sheet is a negative electrode sheet, and the second electrode sheet is a positive electrode sheet. The electrode assembly according to any one of claims 1 to 11.

13. Each of the straight segments is provided with a first tab, and a plurality of the first tabs in each of the structural units are aligned along the first direction; and / or A second tab is provided on each of the second electrode sheets, and each of the structural units includes a plurality of the second electrode sheets, and the plurality of second tabs in each of the structural units are aligned along the first direction. The electrode assembly according to any one of claims 1 to 12.

14. The structural unit further includes a separator film; the first electrode sheet and the second electrode sheet are both combined with the separator film; The separator film is disposed so as to separate the first electrode sheet and the second electrode sheet. The electrode assembly according to any one of claims 1 to 13.

15. The bending segment is provided with a guide portion arranged to guide the bending of the bending segment. The electrode assembly according to any one of claims 1 to 14.

16. The guide portion includes a recessed groove provided in the bending segment.

16. The electrode assembly of claim 15.

17. The folded segment includes a current collector and two active material layers, the two active material layers are provided on both sides of the current collector, The groove is provided in at least one of the active material layers.

17. The electrode assembly of claim 16.

18. The groove is provided in one of the active material layers.

18. The electrode assembly of claim 17.

19. The grooves are provided in both of the two active material layers.

18. The electrode assembly of claim 17.

20. the guide portion further includes a through-hole penetrating the current collector, a region of the current collector corresponding to the recessed groove forms a non-active material layer region, and the through-hole is provided in the non-active material layer region; 20. The electrode assembly of claim 19.

21. the non-active material layer is provided with a plurality of through holes spaced apart along the width direction of the first electrode sheet; 21. The electrode assembly of claim 20.

22. the recessed groove extends along the width direction of the first electrode sheet and penetrates the active material layer; The electrode assembly according to any one of claims 17 to 21.

23. The active material layer is provided with a plurality of recessed grooves arranged at intervals along the width direction of the first electrode sheet. The electrode assembly according to any one of claims 17 to 21.

24. The folded segment includes a current collector and two active material layers, two active material layers are provided on both sides of the current collector, and the guide portion includes a through-hole provided in the bent segment; the through-holes penetrate the current collector and the two active material layers; or the through-holes penetrate the current collector, and the two active material layers cover the through-holes; 16. The electrode assembly of claim 15.

25. the guide portion includes a plurality of the through holes arranged at intervals along the width direction of the first electrode sheet.

25. The electrode assembly of claim 24.

26. The through hole is a rectangular hole.

26. The electrode assembly of claim 20, 21, 24 or 25.

27. The cross section of the through hole is rectangular, and the length direction of the rectangle coincides with the width direction of the first electrode sheet.

27. The electrode assembly of claim 26.

28. The rectangle has a length a and a width b, and satisfies 10≦a / b≦400.

28. The electrode assembly of claim 27.

29. 20≦a / b≦100; 29. The electrode assembly of claim 28.

30. 3 mm≦a≦20 mm, and / or 0.05 mm≦b≦0.3 mm; 30. The electrode assembly according to claim 28 or 29.

31. Housing and A battery cell comprising the electrode assembly according to any one of claims 1 to 30, The electrode assembly is housed within the housing. Battery cell.

32. 32. A battery cell comprising: battery.

33. 32. An electrical device including the battery cell of claim 31, The battery cell is used to provide electrical energy. Electrical equipment.

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