Electrode assemblies, battery cells, batteries, and electrical devices

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] This application relates to the technology of batteries, and more specifically to electrode assemblies, battery cells, batteries, and electrical devices. [Background technology]

[0002] With the development of new energy technologies, batteries are being applied more and more widely, for example, in mobile phones, laptops, battery cars, electric vehicles, electric airplanes, electric boats, electric toy cars, electric toy boats, 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, improving the reliability of electrode assemblies is a challenge that needs to be addressed in battery technology. [Overview of the Initiative]

[0004] Embodiments of the present invention provide an electrode assembly, a battery cell, a battery, and an electrical 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 comprising a plurality of structural units stacked along a first direction, wherein the structural units include a bent segment and a plurality of straight segments, and the first electrode sheet comprises two adjacent straight segments spaced apart along the first direction and connected to one bent segment, and a second electrode sheet having the 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 is a folded structure formed by folded segments and straight segments, and the straight segments of the first electrode sheet are arranged alternately with those of the second electrode sheet. In this way, during manufacturing, the structural units can be formed first with the first electrode sheet and the second electrode sheet, and then the plurality of structural units can be stacked. This reduces the risk of tilting during the molding process of the electrode assembly, thereby reducing the risk of misalignment between 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 two. This allows for a greater number of straight segments in the first electrode sheet in at least one structural unit, effectively improving the manufacturing efficiency of the electrode assembly.

[0008] In some embodiments, the number of straight segments in the first electrode sheet in at least one structural unit is odd. When the number of straight segments in the first electrode sheet is odd, the number of bent segments in the first electrode sheet is even, and the number of bent segments on both sides perpendicular to the first direction in the structural unit 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 become deformable, resulting in better structural stability of the first electrode sheet, reducing the difference in deformation between the two sides of the structural unit, making it less likely for the structural unit to tilt, reducing the risk of misalignment between 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 two. This increases the number of straight segments of the first electrode sheet in each structural unit, which is advantageous in reducing the number of structural units in the electrode assembly, provided that the dimensions along the first direction of the electrode assembly are constant, and further improves the manufacturing efficiency of the electrode assembly.

[0010] In some embodiments, the number of straight segments in the first electrode sheet in each structural unit is odd. In this way, the number of bent segments in 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. When the first electrode sheet is subjected to a force along the first direction, both bent segments on both sides of the structural unit become deformable, the first electrode sheet in each structural unit has good structural stability, and the risk of the structural unit tilting is further reduced, thereby reducing the risk of the electrode assembly tilting.

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

[0012] In some embodiments, the number of straight segments of the first electrode sheet in at least two structural units is not equal. This diversifies the types of structural units in the electrode assembly, allowing multiple structural units to employ multiple combination configurations, improving the versatility of the electrode assembly and enabling it to better adapt to market needs.

[0013] In some embodiments, the structural units include a first structural unit, a second structural unit, and a third structural unit arranged sequentially along the first direction, where 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 both even, and the number of straight segments of the first electrode sheet in the second structural unit is odd. The number of straight segments in the intermediate second structural unit is odd, the number of straight segments in the first and third structural units located on either side of the second structural unit are even, and the number of folded segments on both sides of the second structural unit perpendicular to the first direction is equal. When the combined structure formed by the first, second, and third structural units is subjected to a force along the first direction, the difference in the amount of deformation of the combined structure on both sides perpendicular to the first direction is small, resulting in a combined structure with superior structural stability and less tendency to tilt.

[0014] In some embodiments, along the first direction, the two straight segments located at both ends of the first electrode sheet are the first straight segment and the second straight segment, respectively. 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 in the second direction Towards Along the way, the first straight segment of one structural unit is folded segment Toka The end that is far from the first straight segment and the end that is far from the second straight segment of the other structural unit are located on opposite sides of the electrode assembly, with the second direction being perpendicular to the first direction. The two adjacent bent segments on each side in the second direction of the electrode assembly are neither too far apart nor too close together, resulting in a more rational layout that gives the electrode assembly better structural stability and further reduces the risk of tilting.

[0015] In some embodiments, in the embodiment of the present invention, the number of straight segments in the first electrode sheet of the structural unit is equal to the number of second electrode sheets. In this way, one straight segment corresponds to one second electrode sheet in the structural unit, and an alternating arrangement of straight segments and second electrode sheets in two adjacent structural units can be realized, 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, and the third electrode sheet is provided on at least one side of a plurality of structural units along a first direction, with the third electrode sheet adjacent to the second electrode sheet in 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 the negative electrode sheet, and the second electrode sheet is the positive electrode sheet. This 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, a plurality of first tabs in each structural unit are aligned along a first direction, and / or a second tab is provided on each second electrode sheet, each structural unit includes a plurality of second electrode sheets, and a plurality of second tabs in each structural unit are aligned along the first direction. When the plurality of first tabs in the structural unit are aligned along the first direction, bus bar connection becomes easy. When cutting the first tab, the entire structural unit can be cut, further improving the cutting efficiency of the first tab and the manufacturing efficiency. When the plurality of second tabs in the structural unit are aligned along the first direction, bus bar connection becomes easy. When cutting the second tab, the entire structural unit can be cut, further improving the cutting efficiency of the second tab and the manufacturing efficiency.

[0019] In some embodiments, the structural unit further includes a separator film, both the first electrode sheet and the second electrode sheet are laminated on the separator film, and the separator film is arranged to separate the first electrode sheet and the second electrode sheet. The separator film realizes insulation separation between the first electrode sheet and the second electrode sheet, reducing the risk of internal short circuit of the electrode assembly. Since both the first electrode sheet and the second electrode sheet are laminated on 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 less likely to occur.

[0020] In some embodiments, the bending segment is provided with a guide portion for guiding the bending of the bending segment. The guide portion enables the first electrode sheet to be bent at a predetermined position, improving the folding efficiency of the first electrode sheet, making the folding position more consistent, making the relative position between the straight segment and the second electrode sheet more accurate, and ensuring the reliability of the electrode assembly.

[0021] In some embodiments, the guide portion includes a concave groove provided in the bending segment. The bending segment is thinner in the region where the concave groove is provided, and the concave groove has an excellent guiding effect, so that the first electrode sheet can be more easily bent at the position of the concave groove to correspond to the formed bending segment. Such a guide portion has a simple structure and is easy to form.

[0022] In some embodiments, the bending segment includes a current collector and two layers of active material layers. The two layers of active material layers are provided on both sides of the current collector respectively, and at least one layer of the active material layer is provided with a concave groove. By providing a concave groove in at least one layer of the active material layer of the bending segment, it is possible to thin a part of the bending segment, and the realization method becomes simple.

[0023] In some embodiments, at least one layer of the active material layer is provided with a concave groove. By doing so, the forming difficulty of the first electrode sheet can be reduced.

[0024] In some embodiments, both of the two layers of active material layers are provided with concave grooves. By doing so, the bending segment becomes thinner in the region where the concave groove is provided and is easier to bend.

[0025] In some embodiments, the guide portion further includes a through hole penetrating the current collector. The region of the current collector corresponding to the concave groove forms a non-active material layer region, and the through hole is provided in the non-active material layer region. By arranging the through hole, the rigidity of the non-active material layer region of the current collector is reduced, and the folding effect is reinforced by reducing the rigidity of the non-active material layer region, further improving the folding efficiency of the first electrode sheet. Also, 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 impregnating the electrode sheet with the electrolyte.

[0026] In some embodiments, the non-active material layer region is provided with a plurality of through holes, and the plurality of through holes are spaced apart along the width direction of the first electrode sheet. In this way, living things The rigidity of the current collector in the solid layer region is further reduced, allowing the first electrode sheet to be bent more easily in the inactive material layer region.

[0027] In some embodiments, the grooves extend along the width direction of the first electrode sheet and penetrate the active material layer. Such grooves are easier to mold, and the first electrode sheet is easier to fold in the region of the grooves.

[0028] In some embodiments, the active material layer is provided with a plurality of grooves, which are spaced apart along the width direction of the first electrode sheet. In this way, the first electrode sheet has good bending performance in the region of the plurality of grooves, and the first electrode sheet has sufficient strength in that region, making it less likely to break.

[0029] In some embodiments, the folding segment includes a current collector and two layers of active material, with the two layers of active material provided on both sides of the current collector, and the guide portion includes a through-hole provided in the folding segment. The through-hole penetrates the current collector and the two layers of active material, or the through-hole penetrates the current collector and the two layers of active material cover the through-hole. The reduced rigidity of the region in the folding segment where the through-hole is provided makes it easier to fold the first electrode sheet at the location of the through-hole, thereby forming the folding segment. When the through-hole penetrates the current collector and the two layers of active material, the bending performance of the first electrode sheet in the region of the through-hole is improved. In addition, in a 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. When the through-hole penetrates the current collector and the two layers of active material cover the through-hole, the first electrode sheet has sufficient strength in the region where the through-hole is provided, and the risk of breakage during the bending process of the first electrode sheet is reduced. Furthermore, when forming the first electrode sheet, through holes are first machined into the current collector, and then an active material layer is placed on the surface of the current collector. This allows the active material layer to cover the through holes, reducing the difficulty of forming the first electrode sheet.

[0030] In some embodiments, the guide portion includes a plurality of through holes, which are spaced apart along the width direction of the first electrode sheet. This further reduces the rigidity of the region in the bending segment where the through holes are provided, making the first electrode sheet easier to bend in the region where the through holes are provided.

[0031] In some embodiments, the through-holes are rectangular. Such through-holes have a simple structure and are easy to mold.

[0032] In some embodiments, the cross-section of the through-hole is rectangular, and the length of the rectangle coincides with the width of the first electrode sheet. This allows for more precise folding of the first electrode sheet.

[0033] In some embodiments, the length of the rectangle is a, the width is b, and the condition 10 ≤ a / b ≤ 400 is satisfied. If a / b < 10, the dimensions of the through-hole in the bending direction of the bending segment are large, resulting in poor folding consistency of the first electrode sheet in the region of the through-hole, thus affecting the folding accuracy of the first electrode sheet. If a / b > 400, the dimensions of the through-hole in the bending direction of the bending segment are small, resulting in weak guiding ability of the through-hole for bending the first electrode sheet, which may similarly affect the folding accuracy of the first electrode sheet. Therefore, by setting 10 ≤ a / b ≤ 400, the through-hole becomes an elongated structure that extends along the width direction of the first electrode sheet, improving the consistency of the folding position of the first electrode sheet, making the folding position of the first electrode sheet 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 examples, 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 comprising a housing and an electrode assembly according to one embodiment described in the first aspect, wherein the electrode assembly is housed 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 embodiment described in the second aspect.

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

[0039] To more clearly explain the technical concept of the embodiments of this application, the drawings necessary for the embodiments of this application are briefly described below. It should be understood that the following drawings show only a few embodiments of this application and should not be considered as limiting the scope, and that those skilled in the art can obtain other relevant drawings based on these drawings without expending any creative effort.

[0040] [Figure 1] This is a schematic diagram of the structure of a vehicle according to several embodiments of the present invention. [Figure 2] This is an exploded view of a battery according to some embodiments of the present invention. [Figure 3] This is an exploded view of a battery cell according to some embodiments of the present invention. [Figure 4] This is a schematic diagram of the structure of an electrode assembly according to several embodiments of the present invention. [Figure 5] This is a schematic diagram of the structure of an electrode assembly according to several other embodiments of the present invention. [Figure 6] This is a schematic diagram of the structure of an electrode assembly according to several further embodiments of the present invention. [Figure 7] This is a schematic diagram of the structure of an electrode assembly according to some other embodiments of the present invention. [Figure 8] This is a perspective view of an electrode assembly according to some embodiments of the present application. [Figure 9] Figure 8 is a perspective view of the structural unit. [Figure 10] Figure 9 is a schematic diagram of the structure after the structural unit has been unfolded. [Figure 11] This is a perspective view of a first electrode sheet according to some embodiments of the present application. [Figure 12] This is a schematic diagram of the structure of the first electrode sheet according to some embodiments of the present application. [Figure 13] Figure 12 shows a partial view of the first electrode sheet after it has been unfolded. [Figure 14] Figure 13 is a plan view of the first electrode sheet. [Figure 15] This is a schematic diagram of the structure of the first electrode sheet according to some other embodiments of the present application. [Figure 16] Figure 15 shows a partial view of the first electrode sheet after it has been unfolded. [Figure 17] This is a partial view of the first electrode sheet after unfolding, according to some other embodiments of the present application. [Figure 18] Figure 17 is a plan view of the first electrode sheet. [Figure 19] This is a plan view of the first electrode sheet after unfolding, according to some embodiments of the present application. [Figure 20] This is a plan view of the first electrode sheet after unfolding, according to some other embodiments of the present application. [Figure 21] This is a partial view of the first electrode sheet after unfolding, according to some other embodiments of the present application. [Figure 22] Figure 21 is a plan view of the first electrode sheet. [Figure 23] This is a partial view of the first electrode sheet after unfolding, according to several further embodiments of the present application. [Figure 24] Figure 23 is a plan view of the current collector. [Figure 25] This is a magnified view of area A in Figure 18. [Figure 26] This is a magnified view of area B in Figure 22. [Modes for carrying out the invention]

[0041] To further clarify the purpose, technical concept, and advantages of the embodiments of this application, the technical concept of the embodiments of this application will be clearly described below with reference to the drawings of the embodiments. It is clear that the embodiments described are only some, and not all, embodiments of this application. All other embodiments that can be obtained without creative effort by a person skilled in the art based on the embodiments of this application are all within the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art. In this specification, terms used in the application's description are solely for the purpose of describing specific embodiments and are not intended to limit the application. The terms “includes” and “has,” and any variations thereof, in the description of the application, claims, and drawings are intended to cover non-exclusive “inclusion.” Terms such as “first,” “second,” etc., in the application, claims, or drawings are for distinguishing different subjects and are not intended to describe a particular order or hierarchical relationship.

[0043] As used herein, “Examples” means that certain features, structures, or properties described by reference to the Examples are included in at least one Example of this Application. The term “Examples” as it appears in various parts of this Specification does not necessarily refer to the same Example, nor does it mean that any of the Examples are exclusive, independent, or alternative to the others.

[0044] In this description, unless otherwise specified and limited, the terms “attachment,” “connection,” “connection,” and “mounting” should be understood in a broad sense. For example, the connection may be fixed, detachable, integral, directly, indirectly via an intermediate medium, or internal communication between two elements. A person skilled in the art will be able to understand the specific meaning of these terms in this description depending on the specific circumstances.

[0045] In this application, the terms "and / or" are merely used to describe the relationship between related objects, indicating that three types of relationships are possible. For example, A and / or B can represent three situations: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the letter " / " generally indicates that the related objects before and after it have an "or" relationship.

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

[0047] In this application, "multiple" means two or more (including two).

[0048] In the embodiments of the present invention, the battery cell may be a secondary battery, which refers to a battery cell that can be continuously used by activating the active material through charging after the battery cell has been discharged.

[0049] The battery cell may be a lithium-ion battery, sodium-ion battery, lithium metal battery, lithium sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited thereto.

[0050] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a battery cell, active ions (e.g., lithium ions) reciprocate between the positive and negative electrodes, being intercepted and released. The separator is placed between the positive and negative electrodes and serves to prevent short circuits between them while allowing active ions to pass through.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material provided on at least one surface of the positive electrode current collector.

[0052] As an example, the positive electrode current collector has two opposing surfaces in the thickness direction of itself, and the positive electrode active material is provided on one or both of the two opposing surfaces of the positive electrode current collector.

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

[0054] As an example, the positive electrode active material may include at least one of lithium-containing phosphates, lithium transition metal oxides, and modified compounds thereof. However, this 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 individually 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 (which can also be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), 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 )、 LiRing 0.5 Co 0.2 Mn 0.3 O2(NCM523 which can also be abbreviated as), LiNi 0.5 Co 0.25 Mn 0.25 O2 (NCM 211 which can also be abbreviated as), LiNi 0.6 Co 0.25 Mn 0.25 O2 、 LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM 622 which can also be abbreviated as), LiN i0.8 Co 0.1 Mn 0.1 O2 (NCM 811 which can also be abbreviated as) ) , lithium nickel cobalt aluminum oxide (for example, LiNi 0.8 C o 0.15 Al 0.05 O2) and at least one of their modified compounds, etc., but not limited thereto.

[0055] In some embodiments, a foamed metal can be used for the positive electrode. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, and of course, the positive electrode active material may be provided. As an example, the foamed metal may be filled or / and deposited with a lithium source material, potassium metal or sodium metal, and the lithium source material is 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] As an example, the negative electrode current collector can be a metal foil, foamed metal, or a composite current collector. For example, as a metal foil sheet, silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbide-finished electrodes, carbon, nickel, or titanium can be used. As a foamed metal, foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. A composite current collector may include a polymer base layer and a metal layer. A composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0058] As an 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] As an example, the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode active material is provided on one or both of the two opposing surfaces of the negative electrode current collector.

[0060] As an example, the negative electrode active material may be a negative electrode active material used in battery cells known in the art. 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, this application is not limited to these materials, and other materials used as battery negative electrode active materials may be used. These negative electrode active materials may be used individually 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 separator film in this application is not particularly limited, and any known porous structure separator film having good chemical and mechanical stability can be selected.

[0063] As an 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. If the separator film is a multi-layer composite film, the materials of each layer may be the same or different, and is not particularly limited. The separator may be a single component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0064] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is placed between the positive and negative electrodes and simultaneously performs the functions of ion transport and separation of the positive and negative electrodes.

[0065] In some embodiments, the battery cell further contains an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. In this application, the type of electrolyte is not particularly limited and can be selected according to the needs. The electrolyte may be liquid, gel-like, 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 hexafluoride phosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoride arsenate, 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 also 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-like electrolyte contains a polymer backbone network as the electrolyte and is compounded with an ionic liquid-lithium salt.

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

[0071] Examples of polymer solid electrolytes include polyethers (polyethylene oxide), polysiloxanes, polycarbonates, polyacrylonitriles, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquid lithium salts, and cellulose.

[0072] As an example, inorganic solid electrolytes may be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), sulfide solid electrolytes (crystalline lithium superionic conductor (lithium germanium phosphate sulfur, argyrodite), amorphous sulfide), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0073] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

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

[0075] As an example, multiple positive electrode sheets and multiple negative electrode sheets may be provided, and the multiple positive electrode sheets and multiple negative electrode sheets are arranged in an alternating stacking configuration.

[0076] As an example, there may be multiple positive electrode sheets, and the negative electrode sheets may be folded to form multiple stacked folded segments, with one positive electrode sheet sandwiched between adjacent folded segments.

[0077] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form multiple stacked folded segments.

[0078] For example, multiple separators may be provided, each placed between any adjacent positive or negative electrode sheets.

[0079] For example, the separators may be provided in a continuous manner, or they may be provided between any adjacent positive or negative electrode sheets in the form of folding or winding.

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

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

[0082] For example, a battery cell may be a cylindrical battery cell, a rectangular battery cell, a soft-packaged battery cell, or a battery cell of any other shape. Rectangular battery cells include rectangular-cased battery cells, blade-shaped battery cells, and polygonal prism-shaped batteries, and polygonal prism-shaped batteries are, for example, hexagonal prism-shaped batteries, and are not particularly limited in this application.

[0083] The battery referred to in the embodiments of this application refers to a single physical module comprising one or more battery cells that provides higher voltage and capacity.

[0084] In some embodiments, the battery may be a battery module, and if there are multiple battery cells, multiple battery cells are arranged and fixed together to form a single 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 battery modules are housed in the housing.

[0086] In some embodiments, the housing can be used as part of the vehicle's chassis structure. For example, part of the housing may be at least part of the vehicle's floor, or part of the housing may be at least part of the vehicle's crossbeams and longitudinal beams.

[0087] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, and the like.

[0088] In battery cells, electrode assemblies are generally divided into two types: stacked and wound. In a typical stacked electrode assembly, the 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 arranged alternately with the second electrode sheets. During the process of forming the electrode assembly, as the number of layers of straight segments in the first electrode sheet increases, tilting phenomena are likely to occur in the electrode assembly, causing misalignment of the electrode sheets and reducing the reliability of the electrode assembly.

[0089] In view of this, embodiments of the present application provide an electrode assembly comprising a plurality of structural units, wherein the plurality of structural units are arranged in a stacked manner. The structural unit includes a first electrode sheet and a second electrode sheet having opposite polarities. The first electrode sheet is Folded segment and includes multiple straight segments, where two adjacent straight segments are spaced apart along the first direction, and one Folded segment It is connected to the second electrode sheet and straight along the stacking direction of multiple structural units. segment They are arranged alternately.

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

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

[0092] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, aerospace equipment, electric toys, and power tools. Vehicles may be fuel-fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may include electric vehicles (BEVs), hybrid vehicles, or range-extender vehicles. Aerospace equipment includes airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric boat toys, and electric airplane toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact driver drills, concrete vibrators, and electric planers. Embodiments of the present application are not particularly limited to the electrical devices described above.

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

[0094] Please refer to Figure 1. Figure 1 is a schematic diagram of the structure 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 located 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 the operating power source for the vehicle 1000.

[0095] The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being used to control the battery 100 to supply power to the motor 300, for example, to meet the electrical demands for starting, navigating, and driving the vehicle 1000.

[0096] In some embodiments of the present invention, the battery 100 may provide driving power to the vehicle 1000 not only as a power source for the vehicle 1000, but also as a power source for the vehicle 1000, either in place of or in part 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 invention. The battery 100 consists of a battery cell 10 and a battery cell 10 of Detention do Includes enclosure 20.

[0098] Here, the housing 20 is a component that houses the battery cell 10, and the housing 20 provides a housing space for the battery cell 10, and the housing 20 can employ multiple types of structures. In some embodiments, the housing 20 includes a first part 201 and a second part 202, and the first part 201 and the second part 202 close off each other to define a housing space for housing the battery cell 10. The first part 201 and the second part 202 may be of multiple shapes, such as a rectangular parallelepiped or a cylinder. The first part 201 is a hollow structure with one side open, and the second part 202 is also a hollow structure with one side open, and when the open side of the second part 202 is closed off to the open side of the first part 201, a housing 20 having a housing space may be formed. The first part 201 may be a hollow structure with one side open, and the second part 202 may be a plate-like structure, such that when the second part 202 is closed on the open side of the first part 201, a housing 20 with a storage space is formed. The first part 201 and the second part 202 can be sealed by a sealing element, which may be a sealing ring, sealant, or the like.

[0099] In the battery 100, there may be one battery cell 10 or multiple battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, in parallel, or in a double row. A double row connection means that there are not only series connections but also parallel connections among the multiple battery cells 10. Multiple battery cells 10 may be connected in series, in parallel, or in a double row to form a battery module, and multiple battery modules may be further connected in series, in parallel, or in a double row to form a single whole, which may be housed in the housing 20. All battery cells 10 may be directly connected, in parallel, or in a double row, and the whole composed of all battery cells 10 may be housed in the 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, the electrode assembly 2 being housed within the housing 1.

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

[0102] The casing 11 may be a hollow structure with one end open, or it may be a hollow structure with both opposing ends open. The casing 11 may be in various shapes such as a cylinder or a rectangular parallelepiped. The material of the casing 11 may be one of several types, such as copper, iron, aluminum, steel, or aluminum alloy.

[0103] The end cover 12 is a component that seals the opening of the casing 11 in order to isolate the internal environment of the battery cell 10 from the external environment. Together with the casing 11, the end cover 12 defines a housing space for housing the electrode assembly 2, electrolyte, and other components. The end cover 12 can be connected to the casing 11 by welding or crimping 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, if the casing 11 has a rectangular parallelepiped structure, the end cover 12 has a rectangular plate-shaped structure that matches the housing 1. Furthermore, for example, if the casing 11 has a cylindrical structure, the end cover 12 has a circular plate-shaped structure that matches the casing 11. The material of the end cover 12 may be one of several types, such as copper, iron, aluminum, steel, aluminum alloy, or plastic. The materials of the end cover 12 and the casing 11 may be the same or different.

[0104] In an embodiment where the casing 11 has an opening at one end, one end cover 12 may be provided. In an embodiment where the casing 11 has openings at both opposing ends, two end covers 12 may be provided, each sealing two openings in the casing 11, and the two end covers 12 together with the casing 11 define the housing space.

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

[0106] As an example, as shown in Figure 3, an opening is formed at one end of the casing 11, and there is one end cover 12 in the housing 1, which seals one opening in the casing 11. The end cover 12 is provided with two electrode terminals, which are a positive electrode terminal 3 and a negative electrode terminal 4, respectively. 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 being electrically connected to the positive electrode tab 21 and the negative electrode terminal 4 being electrically connected to the negative electrode tab 22.

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

[0108] The 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 have opposite polarities, 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 electrode assembly 2 may have three or more structural units 23.

[0109] Here, the first electrode sheet 231 is a foldable structure, and after the first electrode sheet 231 is folded, it forms a folded segment 2312 and a plurality of straight segments 2311. The straight segments 2311 are the straight portions of the first electrode sheet 231 that are not folded, and the thickness direction of the straight segments 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 odd or even. Two adjacent structural units 23 may or may not have the same number of straight segments 2311. The folded segment 2312 is the folded portion of the first electrode sheet 231, and the folded segment 2312 is connected to two adjacent straight segments 2311. Along the second direction Y, the folded segment 2312 is connected to the ends of the straight segments 2311, and the second direction Y is perpendicular to the first direction X. The folded segment 2312 may also be arc-shaped, and the folding direction W of the folded segment 2312 is the direction of extension of the arc in which the folded segment 2312 is located. There may be one or more folded segments 2312 in the first electrode sheet 231. The first electrode sheet 231 has one more straight segment 2311 than folded segment 2312. It can be understood that if there is an odd number of straight segments 2311 in the first electrode sheet 231, there is an even number of folded segments 2312, and if there is an even number of straight segments 2311 in the first electrode sheet 231, there is an odd number of folded segments 2312. In some embodiments, the first electrode sheet 231 has 2 to 20 straight segments 2311, and furthermore, the first electrode sheet 231 has 3 to 9 straight segments 2311.This reduces the risk of the first electrode sheet 231 tilting during the folding process, and also allows the first electrode sheet 231 in the structural unit 23 to have excellent stability after molding.

[0110] The second electrode sheet 232 may be a linear sheet 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, there may be one more second electrode sheet 232 than the straight segments 2311 of the first electrode sheet 231, and there may be one less second electrode sheet 232 than the straight segments 2311 of the first electrode sheet 231, and 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 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 each is three. For example, they 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 configuration, and does not limit the provision of other components 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 insulating 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 invention, by dividing the electrode assembly 2 into a plurality of structural units 23, the number of layers of straight segments 2311 of the first electrode sheet 231 in the structural unit 23 is reduced, thereby reducing the risk of the structural unit 23 tilting. During manufacturing, the structural unit 23 can be formed first using the first electrode sheet 231 and the second electrode sheet 232, and then the plurality of structural units 23 can be stacked. This reduces the risk of tilting during the molding process of the electrode assembly 2, thereby reducing the risk of misalignment between electrode sheets and effectively improving the reliability of the electrode assembly 2.

[0114] In some embodiments, referring again to Figure 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 total number of straight segments 2311 in all structural units 23 may be greater than two.

[0116] Taking the example that the electrode assembly 2 has three structural units 23, the number of straight segments 2311 in each of the three structural units 23 may be greater than 2, or the number of straight segments 2311 in two of the structural units 23 may be greater than 2, and the number of straight segments 2311 in the other structural unit 23 may be 2. As shown in Figure 4, the number of straight segments 2311 in two of the structural units 23 may be 2, and the number of straight segments 2311 in the other structural unit 23 may be greater than 2.

[0117] In this embodiment, having more than two straight segments 2311 in at least one structural unit 23 allows for a greater number of straight segments 2311 in at least one structural unit 23, thereby effectively improving the manufacturing efficiency of the electrode assembly 2. For example, when cutting tabs from the first electrode sheet 231 in the structural unit 23, having more straight segments 2311 in the first electrode sheet 231 allows for cutting more tabs at once, thereby improving the manufacturing efficiency of the electrode assembly 2.

[0118] In some embodiments, referring again to Figure 4, the number of straight segments 2311 of the first electrode sheet 231 in at least one structural unit 23 is odd.

[0119] In a structural unit 23 having an odd number of straight segments 2311, the 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 example that the electrode assembly 2 has three structural units 23, the number of straight segments 2311 in each of the three structural units 23 may be odd, or the number of straight segments 2311 in two structural units 23 may be odd and the number of straight segments 2311 in the other structural unit 23 may be even. As shown in Figure 4, the number of straight segments 2311 in two structural units 23 may be even and the number of straight segments 2311 in the other structural unit 23 may be odd.

[0122] When 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 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 acting along the first direction X, both the bent segments 2312 on both sides of the structural unit 23 become deformable, improving the structural stability of the first electrode sheet 231, reducing the difference in the amount of deformation on both sides of the structural unit 23, making it less likely for the structural unit 23 to tilt, reducing the risk of misalignment between the electrode sheets, and improving the reliability of the electrode assembly 2.

[0123] Please refer to Figure 5 for some embodiments. Figure 5 is a schematic diagram of the structure 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 the structural unit 23 may be odd or even. The straight segments 2311 in two adjacent structural units 23 may be equal or not.

[0125] In this embodiment, since the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is greater than two, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 increases. If the dimensions of the electrode assembly 2 along the first direction X are constant, this is advantageous in reducing the number of structural units 23 of the electrode assembly 2, and the manufacturing efficiency of the electrode assembly 2 can be further improved.

[0126] In some embodiments, referring again to Figure 5, the number of straight segments 2311 of the first electrode sheet 231 in each structural unit 23 is odd.

[0127] In a structural unit 23, there may be three, five, seven, or more straight segments 2311. 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 in the first electrode sheet 231 in each structural unit 23 is odd. This ensures that the number of bent segments 2312 in each first electrode sheet 231 is even. The number of bent segments 2312 on both sides perpendicular to the first direction X (second direction Y) in each structural unit 23 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 become deformable. This reduces the difference in deformation between the two sides of the structural unit 23, resulting in excellent structural stability for the first electrode sheet 231 in each structural unit 23, further reducing the risk of tilting of the structural unit 23 and the risk of the electrode assembly 2 tilting.

[0129] In some embodiments, referring again to Figure 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 during the folding process of the first electrode sheet 231 increases. 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, and the risk of the electrode assembly 2 tilting is reduced.

[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] The number of straight segments 2311 of the first electrode sheet 231 in n structural units 23 is not equal, and n≧2, so it can be understood that the number of straight segments 2311 of the first electrode sheet 231 in any two of the n structural units 23 is not equal. As an example, when n=3, the number of straight segments 2311 of the first electrode sheet 231 in three structural units 23 is not equal, so it can be understood that in three structural units 23, the number of straight segments 2311 of the first electrode sheet 231 in any two of the structural units 23 is not equal, for example, one structural unit 23 has two straight segments 2311 of the first electrode sheet 231, another structural unit 23 has three straight segments 2311 of the first electrode sheet 231, and yet another structural unit 23 has four straight segments 2311 of the first electrode sheet 231.

[0133] In this embodiment, the structural units 23 in the electrode assembly 2 are diverse in type, and multiple structural units 23 employ multiple combination forms to improve the variability of the electrode assembly 2 and allow it to better adapt to market needs.

[0134] Refer to Figure 6 for some embodiments. Figure 6 is a schematic diagram of the structure of an electrode assembly 2 according to some further embodiments of the present application. The plurality of structural units 23 include a first structural unit 23a, a second structural unit 23b, and a third structural unit 23c, which are arranged in order along a 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, and the number of straight segments 2311 of the first electrode sheet 231 in the second structural unit 23b is odd.

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

[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] As an example, as shown in Figure 6, there are two straight segments 2311 in the first structural unit 23a and two straight segments 2311 in the third structural unit 23c, while there are three straight segments 2311 in the second structural unit 23b. The first electrode sheet 231 in the first structural unit 23a and the first electrode sheet 231 in the third structural unit 23c have a roughly "U" shaped structure, while the first electrode sheet 231 in the second structural unit 23b has a roughly "S" shaped structure.

[0138] In this embodiment, the straight segments 2311 of the intermediate second structural unit 23b are odd in number, while the straight segments 2311 of the first structural unit 23a and the third structural unit 23c, located on either side of the second structural unit 23b, are even in number. 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 three components, 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. As a result, the combined structure has superior structural stability and is less prone to tilting.

[0139] Refer to Figures 4 to 6 for some embodiments. Along the first direction X, the two straight segments 2311 located at both ends of the first electrode sheet 231 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 two adjacent straight segments 2311, and along the second direction Y, one end of the first straight segment 2311a of one structural unit 23 away from the bent segment 2312 and the other end of the second straight segment 2311b of the other structural unit 23 away from the bent segment 2312 are located on opposite sides of the electrode assembly 2, with the second direction Y being 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 each 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 along the first direction X. If there are two straight segments 2311 in the first electrode sheet 231, it can be understood that the two straight segments 2311 are, respectively, the first straight segment 2311a and the second straight segment 2311b. 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 the other end of the second straight segment 2311b in the other structural unit 23 are located on opposite sides of the electrode assembly 2, and 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 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] Taking the embodiment shown in Figure 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 away from the bent segment 2312 and the other end of the second straight segment 2311b in the second structural unit 23b away 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 away from the bent segment 2312 and the other end of the second straight segment 2311b in the third structural unit 23c away from the bent segment 2312 are located on opposite sides of the electrode assembly 2.

[0144] In this embodiment, the two adjacent bent segments on each side of the electrode assembly 2 in the second direction Y are neither too far apart nor too close together, resulting in a more rational layout. This provides the electrode assembly 2 with superior structural stability and further reduces the risk of tilting.

[0145] In some embodiments, referring again to Figures 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 straight segments 2311 of the second electrode sheet 232.

[0146] Taking the embodiment shown in Figure 6 as an example, 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. In this way, it is 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 also 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, by having one straight segment 2311 and one second electrode sheet 232 in each structural unit 23, an alternating arrangement of straight segments 2311 and second electrode sheets 232 in two adjacent structural units 23 can be achieved. As a result, in two adjacent structural units 23, along the first direction X, the electrode sheet at the top of one structural unit 23 located at the bottom and the electrode sheet at the bottom of the same structural unit 23 located at the top have opposite polarity. This allows each straight segment 2311 and each second electrode sheet 232 in the two adjacent structural units 23 to be fully utilized, which is advantageous for improving the electrical capacity of the battery cell 10.

[0148] Refer to Figure 7 for some embodiments. Figure 7 is a schematic diagram of the structure 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, the third electrode sheet 234 having the same polarity as the first electrode sheet 231. Along a first direction X, the third electrode sheet 234 is provided on at least one side of a plurality of structural units 23, and the third electrode sheet 234 is adjacent to the second electrode sheet 232 in adjacent structural units 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 polarity of the third electrode sheet 234 and the first electrode sheet 231 are the same, the polarity of the third electrode sheet 234 and the second electrode sheet 232 are opposite. It should be understood that if the second electrode sheet 232 is the negative electrode sheet, then the third electrode sheet 234 is the positive electrode sheet, and if the second electrode sheet 232 is the positive electrode sheet, then the third electrode sheet 234 is the negative electrode sheet.

[0150] In the electrode assembly 2, there may be one or two third electrode sheets 234. If the third electrode sheet 234 is provided on only one side of the plurality of structural units 23 along the first direction X, there is one third electrode sheet 234 in the electrode assembly 2, and this third electrode sheet 234 is the outermost electrode sheet in the electrode assembly 2 along the first direction X. If the third electrode sheet 234 is provided on both sides of the plurality of structural units 23 along the first direction X, there are two third electrode sheets 234 in the electrode assembly 2, 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 electrode assembly 2 along the first direction X.

[0151] When we say that the third electrode sheet 234 is adjacent to the second electrode sheet 232 in the adjacent structural unit 23, we mean that the third electrode sheet 234 and the second electrode sheet 232 in the adjacent structural unit 23 are two adjacent electrode sheets, but this does not mean that there are no other members 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 outermost second electrode sheet 232 among the structural units 23 located at the end of the electrode assembly 2 along the first direction X.

[0152] In this embodiment, by making full use of the outermost second electrode sheet 232 of the structural unit 23 located at the end of the electrode assembly 2, 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] Please refer to Figures 4 to 7 for some embodiments. The first electrode sheet 231 is the negative electrode sheet, and the second electrode sheet 232 is the positive electrode sheet. This 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 2. Taking the example that the battery cell 10 is a lithium-ion battery 100, the risk of lithium deposition can be reduced by having the negative electrode sheet cover the positive electrode sheet, further improving the reliability of the electrode assembly 2.

[0154] Refer to Figures 8 and 9 for some embodiments. 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 a 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 a first direction X, and / or each second electrode sheet 232 is provided with a second tab 2321, and each structural unit 23 includes a multiple second electrode sheet 232, and the multiple second tabs 2321 in each structural unit 23 are aligned along a first direction X.

[0155] When 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 multiple structural units 23 can be connected to form a first tab section. When 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 multiple structural units 23 can be connected to form a second tab section. Here, one of the first tab section and the second tab section 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 multiple first tabs 2313 in the structural unit 23 are aligned along the first direction X, busbar connection is facilitated, the entire structural unit 23 can be cut when cutting the first tabs 2313, further improving the cutting efficiency of the first tabs 2313 and thus improving manufacturing efficiency. When multiple second tabs 2321 in the structural unit 23 are aligned along the first direction X, busbar connection is facilitated, the entire structural unit 23 can be cut when cutting the second tabs 2321, further improving the cutting efficiency of the second tabs 2321 and thus improving manufacturing efficiency.

[0157] In some embodiments, please refer to Figures 9 and 10. Figure 10 is a schematic diagram of the structure of the structural unit 23 shown in Figure 9 after unfolding. The structural unit 23 further includes a separator film 233, the first electrode sheet 231 and the second electrode sheet 232 are both compounded with the separator film 233, and the separator film 233 is positioned 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 so as to separate the first electrode sheet 231 from the second electrode sheets 232 on both sides. The separator films 233 and the first electrode sheet 231 are fixed together when the separator films 233 and the first electrode sheet 231 are combined. The second electrode sheet 232 and the separator films 233 are fixed together when the second electrode sheet 232 and the separator films 233 are combined. The first electrode sheet 231 and the second electrode sheets 232 may be combined with the separator films 233 in multiple forms. For example, both the first electrode sheet 231 and the second electrode sheets 232 may be connected to the separator films 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 onto the separator films 233 on both sides of the first electrode sheet 231. Furthermore, the first electrode sheet 231 is repeatedly folded, and finally, an alternating arrangement of the straight segments 2311 of the first electrode sheet 231 and the second electrode sheets 232 is achieved, allowing the structural unit 23 to be formed efficiently and quickly.

[0160] The separator film 233 provides insulating separation between the first electrode sheet 231 and the second electrode sheet 232, reducing the risk of internal short circuits in the electrode assembly 2. Since both the first electrode sheet 231 and the second electrode sheet 232 are composited 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 integration, and the risk of misalignment between the first electrode sheet 231 and the second electrode sheet 232 is low.

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

[0162] The guide portion 23121 is a structure that guides the bending of the bending segment 2312 and is used to bend the first electrode sheet 231 at a predetermined position to form the bending segment 2312. The guide portion 23121 may also be a structure such as a groove or hole provided in the bending segment 2312, and it is sufficient that it guides the first electrode sheet 231 so that it is bent at a predetermined position during the folding process to form the bending segment 2312. Along the bending direction W of the bending segment 2312, the guide portion 23121 may be located at an intermediate position 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, increasing the consistency of the folded position, making the relative position between the straight segment 2311 and the second electrode sheet 232 more accurate, and thus ensuring greater reliability of the electrode assembly 2.

[0164] In some embodiments, referring again to Figure 11, the guide portion 23121 includes a groove 23122 provided in the bent segment 2312.

[0165] The groove 23122 in the guide portion 23121 may be one or more. If there is one groove 23122 in the guide portion 23121, the groove 23122 may extend along the width direction Z of the first electrode sheet. If there are multiple grooves 23122 in the guide portion 23121, the multiple grooves 23122 may be spaced apart 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 two each and perpendicular.

[0166] In this embodiment, the folded segment 2312 is thinner in the region where the groove 23122 is provided, and the groove 23122 has an excellent guiding effect, so that the first electrode sheet 231 can be folded more easily at the position of the groove 23122 to correspond to the formed folded segment 2312. Such a guide portion 23121 has a simple structure and is easy to mold. At the same time, the arrangement of the groove 23122 improves the problem of lithium deposition at the folded portion of the first electrode sheet 231 and improves the service life of the electrode assembly 2.

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

[0168] A groove 23122 may be provided in the single-layer active material layer 23124, or a groove 23122 may be provided in the double-layer active material layer 23124. The depth of the groove 23122 may be less 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, by providing grooves 23122 in at least one active material layer 23124 of the folded segment 2312, it is possible to make a portion of the folded segment 2312 thinner, and the implementation method becomes simpler.

[0170] In some embodiments, referring to Figures 12 to 14, a groove 23122 is provided in one active material layer 23124.

[0171] In the folded segment 2312, the groove 23122 may be provided in the single layer of active material 23124 located inside the current collector 23123, or it may be provided in the single layer of active material 23124 located outside the current collector 23123. Taking the example that the folded segment 2312 is arc-shaped, the radius of the single layer of active material 23124 located outside the current collector 23123 is greater than the radius of the single layer of active material 23124 located inside the current collector 23123. As an example, in the embodiment shown in Figures 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, since grooves 23122 are provided only in one active material layer 23124, the difficulty of molding the first electrode sheet 231 can be reduced. More specifically, when grooves 23122 are provided only in 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 segment 2312 and some of the grooves 23122 are located outside the folded segment 2312, thereby effectively controlling the lithium deposition problem of the first electrode sheet 231 while reducing the difficulty of molding. Furthermore, when grooves 23122 are provided only in one active material layer 23124, when the first electrode sheet 231 is unfolded, all grooves 23122 are located on the same side of the first electrode sheet 231, and the difficulty of the grooving process is lower and the operation is easier compared to when it is necessary to position and align the grooves 23122 on both sides.

[0173] In some embodiments, referring again to Figures 15 and 16, both of the two active material layers 23124 are provided with grooves 23122.

[0174] The grooves 23122 in the two active material layers 23124 are provided in a corresponding manner. For example, the folded segment 2312 is arc-shaped, and the grooves 23122 in the two active material layers 23124 are located in the same radial direction of the folded segment 2312, and along the radial direction of the folded segment 2312, the grooves 23122 in the two active material layers 23124 are located on both sides of the current collector 23123. 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, since both layers of the active material layer 23124 are provided with grooves 23122, the current collector 23123 is not covered by the active material layer 23124 in the region where the groove 23122 is provided, and this region is exposed, becoming the non-active material layer region 23125 of the current collector 23123.

[0176] In this embodiment, since grooves 23122 are provided in both the active material layers 23124 on both sides of the current collector 23123, the folding segment 2312 becomes thinner in the region 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 also be effectively improved.

[0177] Refer to Figure 17 for some embodiments. Figure 17 is a partial view of the unfolded first electrode sheet 231 according to some further embodiments of the present application. The guide portion 23121 further includes a through hole 23126 that penetrates the current collector 23123, and the region of the current collector 23123 corresponding to the groove 23122 forms an inactive material layer region 23125, and the through hole 23126 is provided in the inactive 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 region where the groove 23122 is provided, and correspondingly forms a non-active material layer region 23125.

[0179] The through-holes 23126 provided in the inactive material layer region 23125 may be one or multiple. The through-holes 23126 may have multiple shapes such as circular or rectangular. The through-holes 23126 are located in the inactive material layer region 2312 5 In the width direction, the inactive material layer region 2312 5 It may be provided at an intermediate position. Here, the inactive material layer region 2312 5 The width direction 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, thereby reinforcing the folding effect and further improving the folding efficiency of the first electrode sheet 231. In addition, 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. Furthermore, the problem of lithium deposition on the first electrode sheet 231 can also be effectively improved.

[0181] Please refer to Figure 18 for some embodiments. Figure 18 is a plan view of the first electrode sheet 231 shown in Figure 17. 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.

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

[0183] In this embodiment, the inactive material layer region 23125 is provided with a plurality of through holes 23126 arranged along the width direction Z of the first electrode sheet, thereby further reducing the rigidity of the current collector 23123 in the inactive material layer region 23125, and allowing the first electrode sheet 231 to be bent more easily in the inactive material layer region 23125.

[0184] In some embodiments, referring again to Figures 14 and 18, the groove 23122 extends along the width direction Z of the first electrode sheet and penetrates the active material layer 23124.

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

[0186] Furthermore, regardless of whether the groove 23122 is provided only in the active material layer 23124 on one side of the current collector 23123, or whether the groove 23122 is provided in both sides of the active material layer 23124 of the current collector 23123, the groove 23122 may extend along the first direction X and penetrate the active material layer 23124.

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

[0188] Please refer to Figures 19 and 20 for some embodiments. Figure 19 is a plan view of the first electrode sheet 231 after unfolding according to some embodiments of the present application, and Figure 20 is a plan view of the first electrode sheet 231 after unfolding according to some other embodiments of the present application. The active material layer 23124 is provided with a plurality of grooves 23122, which are spaced apart along the width direction Z of the first electrode sheet.

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

[0190] In the embodiment shown in Figure 19, the region of the current collector 23123 corresponding to the groove 23122 forms an inactive material layer region 23125 (not shown in Figure 19), and the inactive material layer region 23125 does not have a through hole 23126. In the embodiment shown in Figure 20, the region of the current collector 23123 corresponding to the groove 23122 forms an inactive material layer region 23125 (not shown in Figure 20), and the inactive material layer region 23125 has a through hole 23126.

[0191] In this embodiment, the active material layer 23124 is provided with a plurality of grooves 23122 arranged at intervals 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 that region, so the risk of breakage is unlikely to occur.

[0192] In some embodiments, as shown in Figures 21 to 24, Figure 21 is a partial view of the unfolded first electrode sheet 231 according to some other embodiments of the present application, Figure 22 is a plan view of the first electrode sheet 231 shown in Figure 21, Figure 23 is a partial view of the unfolded first electrode sheet 231 according to yet another embodiment of the present application, and Figure 24 is a plan view of the current collector 23123 shown in Figure 23. The bent segment 2312 includes a current collector 23123 and two layers of active material 23124, the two layers of active material 23124 are provided on both sides of the current collector 23123, and the guide portion 23121 includes a through hole 23126 provided in the bent segment 2312. The through-hole 23126 penetrates the current collector 23123 and the two layers of active material 23124, or the through-hole 23126 penetrates the current collector 23123 and the two layers of active material 23124 covers the through-hole 23126.

[0193] The through-hole 23126 provided in the folded segment 2312 may be one or more. The through-hole 23126 may also be of various shapes, such as circular or rectangular.

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

[0195] In this embodiment, the rigidity of the region in the folded segment 2312 where the through-hole 23126 is provided is reduced, making the first electrode sheet 231 easier to fold at the location of the through-hole 23126, thereby forming the folded segment 2312. When the through-hole 23126 penetrates the current collector 23123 and the two layers of active material 23124, the bending performance of the first electrode sheet 231 in the region where the through-hole 23126 is provided is improved. 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-hole 23126 penetrates the current collector 23123 and the two layers of active material 23124 cover the through-hole 23126, the first electrode sheet 231 has sufficient strength in the region where the through-hole 23126 is provided, and the risk of breakage during the bending process of the first electrode sheet 231 is low. Furthermore, when forming the first electrode sheet 231, the through-hole 23126 is first processed in the current collector 23123, and then the active material layer 23124 is placed on the surface of the current collector 23123, so that the active material layer 23124 covers the through-hole 23126, thereby reducing the difficulty of forming the first electrode sheet 231.

[0196] In some embodiments, referring again 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 folded segment 2312 may be two, three, four, five, or more.

[0198] In this embodiment, the folded segment 2312 has a third 1 train By providing multiple through-holes 23126 arranged along the width direction Z of the electrode sheet, the rigidity of the region in the folded segment 2312 where the through-holes 23126 are provided is further reduced, making the first electrode sheet 231 easier to fold in the region where the through-holes 23126 are provided.

[0199] In some embodiments, the through hole 23126 is a rectangular hole.

[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 folded 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 mold.

[0202] In some embodiments, as shown in Figures 18, 20, 22, and 24, the cross-section of the through-hole 23126 is rectangular, and the length 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 in the rectangle, the longer side is longer than the shorter side.

[0204] In this embodiment, the length direction of the through-hole 23126 coincides with the width direction Z of the first electrode sheet, thereby making the folding position of the first electrode sheet 231 more precise.

[0205] In some embodiments, please refer to Figures 25 and 26. Figure 25 is a partial enlargement of area A in Figure 18, and Figure 26 is a partial enlargement of area B in Figure 22. The length of the rectangle is a, the width is b, and the condition 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, or 400, or any range value between the two.

[0207] If a / b < 10, the dimensions of the through-hole 23126 in the bending direction W of the bending segment 2312 are large, resulting in poor folding consistency of the first electrode sheet 231 in the region of the through-hole 23126, which affects the folding accuracy of the first electrode sheet 231. If a / b > 400, the dimensions of the through-hole 23126 in the bending direction W of the bending segment 2312 are small, resulting in weak bending guide capability of the through-hole 23126 for the first electrode sheet 231, which similarly affects the folding accuracy of the first electrode sheet 231. Therefore, by setting 10 ≤ a / b ≤ 400, the through-hole 23126 becomes an elongated structure that extends along the width direction Z of the first electrode sheet, improving the consistency of the folding position of the first electrode sheet 231, making the folding position of the first electrode sheet 231 more accurate, and improving the folding efficiency of the first electrode sheet 231.

[0208] In some examples, 20 ≤ a / b ≤ 100.

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

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

[0211] In some examples, 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, or 20mm, or any range value between the two.

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

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

[0215] The embodiments of the present application provide a battery 100 including a battery cell 10 according to any of the embodiments described above.

[0216] Embodiments of the present application provide an electrical device including a battery cell 10 according to any of the above embodiments for providing electrical energy.

[0217] Embodiments of the present invention further provide an electrode assembly 2 comprising a plurality of structural units 23, wherein the plurality of structural units 23 are stacked along a first direction X, and each structural unit 23 includes a first electrode sheet 231, a second electrode sheet 232, and a separator film 233, wherein the separator film 233 is composited on both sides of the first electrode sheet 231, the second electrode sheet 232 is composited 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. The first electrode sheet 231 has a foldable structure and comprises a folded segment 2312 and a plurality of straight segments 2311, wherein two adjacent straight segments 2311 are 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. The second electrode sheet 232 and the straight segments 2311 are arranged alternately along the first direction X. In the structural unit 23, the number of straight segments 2311 in the first electrode sheet 231 is equal to the number of straight segments 2311 in the second electrode sheet 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 number of straight segments 2311 of the first electrode sheet 231 in at least two structural units 23 is not equal.

[0219] The folded segment 2312 is provided with a groove 23122, which is positioned to guide the folding of the folded segment 2312. The folded segment 2312 includes a current collector 23123 and two layers of active material 23124, the two layers of active material 23124 being provided on both sides of the current collector 23123, and both layers of active material 23124 are provided with grooves 23122. The area of ​​the current collector 23123 corresponding to the grooves 23122 forms an inactive material layer region 23125, and 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 holes 23126 is rectangular, and the length of the rectangle coincides with the width direction Z of the first electrode sheet. The length of the rectangle is a, the width is b, and the following conditions are met: 10 ≤ a / b ≤ 400, 3 mm ≤ a ≤ 20 mm, and 0.05 mm ≤ b ≤ 0.3 mm.

[0220] In the above embodiment, by dividing the electrode assembly 2 into a plurality of structural units 23, the number of layers of straight segments 2311 of the first electrode sheet 231 in the structural unit 23 is reduced, thereby reducing the risk of the structural unit 23 tilting. The risk of tilting after the plurality of structural units 23 are stacked is reduced, thereby reducing the risk of misalignment between electrode sheets and effectively improving the reliability of the electrode assembly 2. Since the number of straight segments 2311 of the first electrode sheet 231 in at least one structural unit 23 is odd, 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 acting along the first direction X, both bent segments 2312 on both sides of the structural unit 23 become deformable, improving the structural stability of the first electrode sheet 231, making it less likely for the structural unit 23 to tilt, reducing the risk of misalignment between electrode sheets, and improving the reliability of the electrode assembly 2. Since the number of straight segments 2311 of the first electrode sheet 231 is not equal in at least two structural units 23, the types of structural units 23 in the electrode assembly 2 become diverse, and multiple structural units 23 can adopt multiple combination forms, improving the versatility of the electrode assembly 2 and allowing it to better adapt to market needs. In addition, since grooves 23122 are provided in both active material layers 23124 of the folding segment 2312, the first electrode sheet 231 is made easier to fold at the position of the grooves 23122, which guides the folding of the first electrode sheet 231, improving the folding efficiency of the first electrode sheet 231 and increasing the consistency of the folding position. Since multiple through holes 23126 are spaced apart in the inactive material layer region 23125 of the current collector 23123, the rigidity of the current collector 23123 in the inactive material layer region 23125 can be effectively reduced. As a result, the first electrode sheet 231 can be bent more easily in the inactive material layer region 23125, and the problem of lithium deposition on the first electrode sheet 231 can be effectively improved.Furthermore, since 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, the through-hole 23126 becomes an elongated structure that extends along the width direction Z of the first electrode sheet, improving the consistency of the folding position of the first electrode sheet 231, making the folding position of the first electrode sheet 231 more accurate, and improving the folding efficiency of the first electrode sheet 231.

[0221] Furthermore, the embodiments and features described herein can be combined with each other, provided that no contradictions arise.

[0222] The above embodiments are merely illustrative of the technical concept of the present application and are not intended to limit the present application. Those skilled in the art will be able to modify and change the present application in various ways. Any modifications, equivalent substitutions, improvements, etc., made without departing from the concept and principles of the present application should 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 section, 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 terminal, 4: Negative 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 the first electrode sheet

Claims

1. An electrode assembly, It includes a plurality of structural units stacked along a first direction, The aforementioned structural unit is A first electrode sheet comprising 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, The device includes a second electrode sheet having the opposite polarity to the first electrode sheet and arranged alternately with the straight segments along the first direction, The plurality of structural units include a first structural unit, a second structural unit, and a third structural unit arranged sequentially and continuously along the first direction. 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 both even numbers. The second structural unit has an odd number of straight segments in the first electrode sheet and an even number of folded segments in the first electrode sheet. Along the first direction, the two straight segments located at both ends of the first electrode sheet are, respectively, the first straight segment and the second straight segment. Each of the combinations of adjacent first structural units and second structural units, and each of the combinations of second structural units and third structural units, The first straight segment of one structural unit and the second straight segment of the other structural unit are two straight segments adjacent to each other in the first direction. One end of the first straight segment in one of the structural units, located opposite to the bent segment, and one end of the second straight segment in the other structural unit, located opposite to the bent segment, are each located on both sides of the electrode assembly in the second direction. The second direction is perpendicular to the first direction. Electrode assembly.

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

3. The number of straight segments of the first electrode sheet in each of the structural units is greater than two. The electrode assembly according to claim 1.

4. 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 claim 1.

5. In the structural unit, the number of straight segments of the first electrode sheet is equal to the number of segments of the second electrode sheet. The electrode assembly according to claim 1.

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

7. The first electrode sheet is a negative electrode sheet, and the second electrode sheet is a positive electrode sheet. The electrode assembly according to claim 1.

8. 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 Each of the second electrode sheets is provided with a second tab, and each of the structural units includes a plurality of the second electrode sheets, and the plurality of the second tabs in each of the structural units are aligned along the first direction. The electrode assembly according to claim 1.

9. The structural unit further includes a separator film, Both the first electrode sheet and the second electrode sheet are composited with the separator film. The separator film is arranged to separate the first electrode sheet and the second electrode sheet. The electrode assembly according to claim 1.

10. The folding segment is provided with a guide portion that is arranged to guide the folding of the folding segment. The electrode assembly according to claim 1.

11. The guide portion includes a groove provided in the bending segment, The electrode assembly according to claim 10.

12. The aforementioned folded segment includes a current collector and two layers of active material. The two active material layers are provided on both sides of the current collector. The groove is provided in at least one layer of the active material layer. The electrode assembly according to claim 11.

13. The groove is provided in one layer of the active material. The electrode assembly according to claim 12.

14. Both of the two active material layers are provided with the grooves. The electrode assembly according to claim 12.

15. The guide portion further includes a through hole that penetrates the current collector, The region of the current collector corresponding to the groove forms an inactive material layer region, and the through hole is provided in the inactive material layer region. The electrode assembly according to claim 14.

16. The inactive material layer region is provided with a plurality of through holes arranged at intervals along the width direction of the first electrode sheet. The electrode assembly according to claim 15.

17. The groove extends along the width direction of the first electrode sheet and penetrates the active material layer. The electrode assembly according to claim 12.

18. The active material layer is provided with a plurality of grooves arranged at intervals along the width direction of the first electrode sheet. The electrode assembly according to claim 12.

19. The aforementioned folded segment includes a current collector and two layers of active material. The 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-hole penetrates the current collector and the two layers of the active material, or The through-hole penetrates the current collector, and the two layers of the active material cover the through-hole. The electrode assembly according to claim 10.

20. The guide portion includes a plurality of through holes arranged at intervals along the width direction of the first electrode sheet. The electrode assembly according to claim 19.

21. The through hole is a rectangular hole. The electrode assembly according to claim 15.

22. The cross-section of the through hole is rectangular, and the length of the rectangle coincides with the width of the first electrode sheet. The electrode assembly according to claim 21.

23. The rectangle has length a and width b, and satisfies 10 ≤ a / b ≤ 400. The electrode assembly according to claim 22.

24. 20 ≤ a / b ≤ 100. The electrode assembly according to claim 23.

25. 3 mm ≤ a ≤ 20 mm and / or 0.05 mm ≤ b ≤ 0.3 mm, The electrode assembly according to claim 23.

26. Housing and A battery cell comprising an electrode assembly according to any one of claims 1 to 25, The electrode assembly is housed within the housing. Battery cell.

27. Including the battery cell described in claim 26, battery.

28. An electrical device comprising a battery cell as described in claim 26, The aforementioned battery cell is used to provide electrical energy. Electrical device.

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