Battery cell, battery device, energy storage device, and electric device

Abstract

The application discloses a battery monomer, a battery device, an energy storage device and a power utilization device. The battery monomer comprises a shell, a pole assembly and at least one electrode assembly. The shell comprises a shell body with an opening on one side in a first direction and an end cover for closing the opening. The end cover and the shell body form a containing cavity. The pole assembly is arranged on the end cover. The electrode assembly is arranged in the containing cavity. The electrode assembly comprises a main body and at least one tab assembly. The tab assembly comprises a plurality of tabs which are sequentially stacked and arranged on the side of the main body facing the end cover. At least part of the plurality of tabs is welded to the pole assembly. The same tab has an overlapping part in the first direction. In the same tab assembly, the intersection number of all tabs with any straight line passing through the welding position in the first direction is not more than the total number of all tabs. The battery monomer, the battery device, the energy storage device and the power utilization device provided by the application have high volumetric energy density.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, energy storage device, and power consumption device. Background Technology

[0002] The application of new energy batteries in daily life and industry is becoming increasingly widespread. For example, new energy vehicles equipped with batteries are already widely used, and batteries are also increasingly being applied in energy storage. In new energy vehicles equipped with batteries, the batteries can provide all or part of the power. In the field of energy storage, batteries can be installed in energy storage boxes or directly on the user side.

[0003] With the continuous development of battery technology, the industry is constantly raising the requirements for the volumetric energy density of batteries. Utility Model Content

[0004] To address the aforementioned technical problems, this application provides a battery cell, battery device, energy storage device, and power consumption device with high volumetric energy density.

[0005] This application is achieved through the following technical solution.

[0006] The first aspect of this application provides a battery cell, comprising: a housing, the housing including a shell having an opening on one side along a first direction and an end cap closing the opening, the end cap and the shell forming a receiving cavity; at least one terminal post assembly disposed on the end cap; and at least one electrode assembly disposed within the receiving cavity, the electrode assembly including a main body and at least one tab assembly, the tab assembly including a plurality of tabs extending from the side of the main body facing the end cap and stacked sequentially, at least a portion of the plurality of tabs being welded to the terminal post assembly, the same tab having an overlapping portion in the first direction, and in the same tab assembly, the number of intersections of all tabs with any straight line passing through the welding portion along the first direction does not exceed the total number of all tabs.

[0007] In the technical solution of this application, the same tab has an overlapping portion in the first direction, that is, the tab is bent in the first direction, and the size of the tab in the first direction is reduced; and, in the same tab assembly, the number of intersections between all tabs and any straight line passing through the welding part along the first direction does not exceed the total number of all tabs. Therefore, the number of overlapping layers of all tabs in the tab assembly along the first direction does not exceed the number of tabs in the tab assembly. The size of the tab assembly along the first direction can be no greater than the thickness of a single tab multiplied by the number of tabs. Thus, the size of the tab assembly along the first direction can be reduced, thereby reducing the space occupied by the tab assembly in the first direction and improving the volumetric energy density of the battery cell.

[0008] In some embodiments, the electrode assembly is a wound structure. The main body of the electrode assembly includes a straight portion and two corner portions respectively disposed at both ends of the straight portion along a second direction. The stacking direction of the straight portion is consistent with a third direction. The first direction, the second direction and the third direction are perpendicular to each other. At least a portion of all the tabs in the same tab assembly extend from the same corner portion.

[0009] A tab is provided at the corner of the wound electrode assembly. Since the corner is semi-circular in the cross section perpendicular to the first direction, the multiple layers of tabs that make up the tab assembly are wrapped around each other in sequence, which helps to improve the interaction force between the tabs. In addition, the tabs have overlapping parts in the first direction, which allows adjacent tabs to be in close contact with each other, forming a compact tab assembly. This not only facilitates the welding operation between the tab assembly and the pole assembly, but also allows the size of the tabs along the first direction to be relatively small.

[0010] In some embodiments, the electrode assembly is formed by winding a laminate including a positive electrode and a negative electrode, with a spacer sandwiched between the positive and negative electrode. At least one tab assembly includes a positive tab assembly, and the portion of the positive electrode near the end cap extending beyond the spacer includes a plurality of tabs arranged sequentially at intervals along the winding direction. The plurality of tabs of the positive electrode are stacked sequentially to form a positive tab assembly. And / or, at least one tab assembly includes a negative tab assembly, and the portion of the negative electrode near the end cap extending beyond the spacer includes a plurality of tabs arranged sequentially at intervals along the winding direction. The plurality of tabs of the negative electrode are stacked sequentially to form a negative tab assembly.

[0011] Thus, a wound electrode assembly is formed by winding the positive electrode, negative electrode, and separator, and the size of the tabs of the electrode assembly along the first direction can be reduced, thereby reducing the space occupied by the tabs in the first direction and improving the volumetric energy density of the battery cell.

[0012] In some embodiments, the electrode assembly has two or more and is arranged sequentially along a third direction.

[0013] The capacity of a single battery cell can be increased by placing two or more electrode assemblies inside the casing.

[0014] In some embodiments, a solder mark is formed on the end face of the pole assembly facing away from the receiving cavity.

[0015] In this way, metal impurities generated during welding remain on the outside and do not enter the inside, reducing the risk of short circuits caused by metal impurities puncturing the separator. Moreover, welding from the outside simplifies the assembly process of battery cells, thus improving production efficiency.

[0016] In some embodiments, the electrode assembly includes an electrode post, which is directly welded to an electrode tab.

[0017] In this way, by directly connecting the pole and the tab, the space occupied in the first direction is further reduced, and the volumetric energy density is increased.

[0018] In some embodiments, the battery cell further includes an insulating member supported between the body portion and the end cap, the insulating member having a through hole through which all tabs of the same tab assembly pass and at least some tabs are welded to the terminal post.

[0019] In this way, the terminal post and the tab are directly connected, further reducing the space occupied in the first direction and further improving the volumetric energy density of the battery cell. By placing an insulating component between the main body and the end cap of the electrode assembly, the probability of electrical continuity between the end cap and the main body can be reduced, lowering the risk of short circuits. Furthermore, the supporting effect of the insulating component improves the structural stability of the tab assembly. In addition, the inner wall of the through hole acts as a limiter on the outer periphery of the tab assembly, reducing the probability of the tab spreading outwards when welding the terminal post from the outside, thus helping to maintain the shape of the tab assembly and improving its conductivity.

[0020] In some embodiments, the electrode assembly includes an electrode and an adapter plate. The electrode is disposed on an end cap, and the adapter plate is disposed in a receiving cavity. The end of the electrode facing the receiving cavity is welded to the adapter plate, and the adapter plate is welded to the electrode tab.

[0021] The use of adapter plates for welding connections simplifies the connection process. Furthermore, the adapter plates facilitate the electrical connection of multiple tab assemblies to the same pole, further simplifying the operation.

[0022] In some embodiments, the surface of the adapter piece facing away from the end cap is a first plane, and the adapter piece is welded to the electrode tab through the first plane.

[0023] By setting the surface of the adapter plate facing away from the end cap to be flat, and this flat surface is connected to the tab, the distance between the adapter plate and the main body of the electrode assembly is equal to the size of the tab along the first direction. This makes the distance between the adapter plate and the main body smaller, reducing the occupancy of the cavity and increasing the volumetric energy density of the battery cell.

[0024] In some embodiments, the surface of the adapter plate facing the end cap is a second plane, and the adapter plate is welded to the pole post through the second plane.

[0025] Thus, the adapter plate has a flat plate structure, which is simple in structure and molding process, reducing manufacturing costs. In addition, it helps to further reduce the space occupied in the first direction, thereby further improving the volumetric energy density of the battery cell.

[0026] In some embodiments, the maximum thickness of the adapter piece is in the range of 0.8 mm to 1.5 mm.

[0027] In this way, by setting the thickness of the adapter piece within a relatively thin range, multiple tab assemblies can be indirectly connected to the same terminal post, without affecting the volumetric energy density of the battery cell due to excessive thickness.

[0028] In some embodiments, the pole, adapter plate, and electrode tab are integrally welded.

[0029] The tab, adapter plate, and pole are integrally welded together using a welding process, connecting these three components into a single unit. This integrated welding improves welding efficiency.

[0030] In some embodiments, a solder mark is formed on the end face of the pole facing away from the receiving cavity.

[0031] Metal impurities generated by external penetration welding remain on the outside of the casing and do not enter the inside, reducing the risk of short circuits caused by metal impurities puncturing the separator. Furthermore, external welding simplifies the assembly process of individual battery cells, improving production efficiency.

[0032] In some embodiments, the electrode assembly further includes at least one boss adjacent to the tab assembly. The boss includes a plurality of sheets that extend from one side of the body portion toward the end cap and are stacked sequentially. Along a first direction, the size of the sheets is smaller than the size of the tab.

[0033] When performing operations such as flattening the tabs, which cause the tabs to bend, the tabs are prone to shedding debris. In other words, debris is easily generated near the tabs. Therefore, a protrusion is set near the tabs to prevent debris from entering the main body and piercing the isolation component, thereby reducing the risk of short circuit.

[0034] In some embodiments, at least one tab assembly includes a positive tab assembly and a negative tab assembly, wherein the tab of the positive tab assembly is a positive tab and the tab of the negative tab assembly is a negative tab, the positive tab assembly is connected to a corner portion and the negative tab assembly is connected to another corner portion.

[0035] Thus, the two corner sections are connected to the positive and negative electrodes respectively, which makes the distance between the positive and negative electrodes larger, reducing the risk of short circuits. In addition, it makes the structure of the positive and negative electrode components compact, allowing the dimensions of the two along the first direction to be relatively small.

[0036] In some embodiments, at least one electrode assembly includes a first electrode assembly and a second electrode assembly, wherein the first electrode assembly is welded to a positive electrode tab assembly and the second electrode assembly is welded to a negative electrode tab assembly.

[0037] Thus, the arrangement of the first and second terminal components facilitates the connection of the positive and negative electrode tabs with conductive components such as the busbar, allowing the current of the battery cell to be discharged through the first terminal component and introduced through the second terminal component.

[0038] In some embodiments, the surface of the positive electrode tab assembly facing the negative electrode tab assembly is parallel to a first direction; and / or, the surface of the negative electrode tab assembly facing the positive electrode tab assembly is parallel to a first direction.

[0039] This design eliminates the need for repeated orientation adjustments during electrode cutting, thus reducing material waste.

[0040] In some embodiments, the surface of the positive electrode tab assembly facing the negative electrode tab assembly extends obliquely from one end of the connecting body portion to the end away from the body portion toward the side away from the negative electrode tab assembly; and / or, the surface of the negative electrode tab assembly facing the positive electrode tab assembly extends obliquely from one end of the connecting body portion to the end away from the body portion toward the side away from the positive electrode tab assembly.

[0041] This design reduces the risk of cracking between the electrode and the main body during operations that cause the electrode to bend, such as flattening.

[0042] In some embodiments, an arc-shaped surface is formed at the connection between the surface of the positive electrode tab assembly facing the negative electrode tab assembly and the end face of the main body; and / or, an arc-shaped surface is formed at the connection between the surface of the negative electrode tab assembly facing the positive electrode tab assembly and the end face of the main body.

[0043] This allows the surface of the tab assembly and the end face of the main body to transition through an arc-shaped surface, improving the reliability of the connection between the two and reducing the risk of cracking between the tab and the main body during operations that cause the tab to bend, such as flattening.

[0044] In some embodiments, the electrode assembly is a wound structure. The main body of the electrode assembly includes a straight portion and two corner portions respectively disposed at both ends of the straight portion along the second direction. The stacking direction of the straight portion is consistent with the third direction. The first direction, the second direction and the third direction are perpendicular to each other. The ratio of the size of the electrode tab along the first direction to the size of the electrode assembly along the third direction is between 0.125 and 0.15.

[0045] Thus, by setting the ratio of the size of the tab along the first direction to the size of the electrode assembly along the third direction in the range of 0.125 to 0.15, the size of the tab along the first direction is relatively small, which is beneficial to improving the volumetric energy density of the battery cell. Furthermore, the height of the tab is not so small that it would affect the welding with the terminal assembly.

[0046] In some embodiments, the size of the tab is in the range of 0.5 mm to 1.5 mm along the first direction.

[0047] Thus, by setting the size of the tab along the first direction to be in the range of 0.5mm to 1.5mm, the size of the tab along the first direction is significantly reduced, thereby reducing the space occupied in the first direction and increasing the volumetric energy density of the battery cell. Furthermore, the above-mentioned size range reduces the probability that the tab will penetrate into the main body and burn the separator when welding it to the electrode assembly due to the tab being too small, thereby reducing the risk of short circuit in the electrode assembly.

[0048] A second aspect of this application provides a battery device comprising a plurality of battery cells provided in the first aspect.

[0049] Because the battery cells provided in the first aspect have high volumetric energy density, the battery device comprising multiple battery cells provided in the first aspect has high volumetric energy density.

[0050] A third aspect of this application provides an energy storage device, which includes a plurality of battery cells provided in the first aspect or a plurality of battery devices provided in the second aspect, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0051] Since the battery cells provided in the first aspect have high volumetric energy density and the battery devices provided in the second aspect have high volumetric energy density, the energy storage device comprising a plurality of battery cells provided in the first aspect or a plurality of battery devices provided in the second aspect has high volumetric energy density.

[0052] The fourth aspect of this application provides an electrical device that includes a plurality of battery cells provided in the first aspect or a plurality of battery devices provided in the second aspect, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0053] Since the battery cells provided in the first aspect have high volumetric energy density and the battery devices provided in the second aspect have high volumetric energy density, the power-consuming device including multiple battery cells provided in the first aspect or multiple battery devices provided in the second aspect has high volumetric energy density.

[0054] The beneficial effects of the embodiments disclosed herein include: providing a battery cell, battery device, energy storage device, and power consumption device with high volumetric energy density. Attached Figure Description

[0055] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0056] Figure 1 This is a schematic diagram of the structure of a vehicle according to one or more embodiments;

[0057] Figure 2 This is an exploded perspective view of a battery device according to one or more embodiments;

[0058] Figure 3 A three-dimensional structural schematic diagram of a battery cell according to one or more embodiments;

[0059] Figure 4 This is a three-dimensional structural schematic diagram of an electrode assembly according to one or more embodiments;

[0060] Figure 5 for Figure 4 Sectional view at point AA;

[0061] Figure 6 A front view of a first structure of an electrode assembly according to one or more embodiments;

[0062] Figure 7 An exploded perspective view of a portion of the structure of a battery cell according to one or more embodiments;

[0063] Figure 8 This is a three-dimensional structural schematic diagram of two adapter pieces according to one or more embodiments;

[0064] Figure 9 A front view of the adapter piece according to one or more embodiments;

[0065] Figure 10 A top view of a structure formed by welding multiple electrode assemblies with two adapter plates according to one or more embodiments;

[0066] Figure 11 A three-dimensional structural schematic diagram of a first structure of multiple electrode assemblies according to one or more embodiments;

[0067] Figure 12 This is a three-dimensional structural schematic diagram of a second structure of multiple electrode assemblies according to one or more embodiments;

[0068] Figure 13 A front view of a second structure of an electrode assembly according to one or more embodiments;

[0069] Figure 14 This is an exploded structural diagram of the end cap structure of a battery cell according to one or more embodiments.

[0070] Figure 15 This is a three-dimensional structural diagram of the end cap structure of a battery cell according to one or more embodiments;

[0071] Figure 16 A flowchart of a method for manufacturing a battery device according to one or more embodiments;

[0072] Figure 17 This is a flowchart illustrating the manufacturing of an electrode assembly in a battery device manufacturing method according to one or more embodiments;

[0073] Figure 18 This is a three-dimensional structural diagram of one aspect of the process of winding to form an electrode assembly according to one or more embodiments;

[0074] Figure 19 This is a top view of another aspect of the process of winding to form an electrode assembly according to one or more embodiments;

[0075] Figure 20 This is a front view of the positive electrode sheet in its unfolded state according to one or more embodiments;

[0076] Figure 21 This is a front view of the negative electrode sheet in an unfolded state according to one or more embodiments.

[0077] Explanation of reference numerals in the attached figures

[0078] 1000 Vehicle; 100 Battery Unit; 200 Controller; 300 Motor; 10 Housing; 101 First Housing; 102 Second Housing; 20 Battery Cells; 1 Electrode Assembly; 11 Positive Electrode; 12 Negative Electrode; 13 Separator; 14 Tab Assembly; 14a Positive Tab Assembly; 14b Negative Tab Assembly; 141 Tab; 142 First Side; 143 Curved Surface; 15 Boss; 151 Sheet; 16 Main Body; 161 Straight Section; 162 Corner Section; 2 Shell; 21 End cap; 211 First pole mounting hole; 212 Second pole mounting hole; 22 Housing; 3 Pole assembly; 3a First pole assembly; 3b Second pole assembly; 31 Pole; 31a First pole; 31b Second pole; 311 Body part; 312 Protrusion; 313 First groove; 314 Second groove; 32 Adapter piece; 321 First plane; 322 Second plane; 5 Insulator; 51 Through hole; 6 Pressure relief mechanism; 71 First upper plastic; 72 Second upper plastic; 73 Lower plastic. Detailed Implementation

[0079] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification and the foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0081] In the description of the embodiments of this application, technical terms such as "first," "second," and "third" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0082] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0083] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects are in an "or" relationship.

[0084] In the description of the embodiments of this application, the technical terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0085] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0086] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical term "contact" should be interpreted broadly, and can be direct contact, contact through an intermediate medium layer, contact between two contacting parties with substantially no interaction force, or contact between two contacting parties with interaction force.

[0087] The following is a detailed description of this application.

[0088] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0089] A larger battery capacity stores more electrical energy, enabling devices to operate for longer periods and significantly extending battery life. Furthermore, a larger capacity battery means fewer charging cycles, reducing the inconvenience of frequent charging for users and contributing to longer battery lifespan. Additionally, a larger capacity battery reduces the risk of device interruption due to low power, improving user experience and satisfaction. The volumetric energy density of a battery directly relates to its capacity for a given volume; therefore, improving volumetric energy density is one of the key research topics in the industry.

[0090] The inventors of this application discovered that in some battery cells, the multi-layered tabs are first gathered together towards the center and then bent to the same side. The portion where the multi-layered tabs gather together forms a gathered section, and the portion that is gathered into a uniform thickness and then bent forms a bent section. In this structure, because the tabs in the bent section are stacked sequentially along the height direction, the dimension of the bent section along the height direction is not less than the thickness of a single tab multiplied by the total number of tabs. Furthermore, most of the tabs in the gathered section also overlap in the height direction, and the gathered section also occupies a large space in the height direction. Therefore, in the height direction, the overall structure formed by the gathered section and the bent section is significantly larger than the thickness of a single tab multiplied by the total number of tabs, resulting in a large space occupation problem, which affects the volumetric energy density of the battery cell.

[0091] The inventors of this application discovered through research that by reducing the total number of overlapping layers of tabs in the height direction, the height of the tabs can be reduced, the space occupied by the tabs in the height direction can be reduced, and the volumetric energy density of the battery cell can be increased.

[0092] Based on this design concept, the inventors of this application have designed a battery cell, which includes a casing, at least one terminal post assembly, and at least one electrode assembly. The casing includes a shell with an opening on one side along a first direction and an end cap that closes the opening. The end cap and the shell form a receiving cavity. At least one terminal post assembly is disposed on the end cap. At least one electrode assembly is disposed in the receiving cavity. The electrode assembly includes a main body and at least one tab assembly. The tab assembly includes a plurality of tabs that extend from the side of the main body facing the end cap and are stacked sequentially. At least a portion of the plurality of tabs is welded to the terminal post assembly. The same tab has an overlapping portion in the first direction. In the same tab assembly, the number of times all tabs intersect with any straight line passing through the welding part along the first direction does not exceed the total number of all tabs.

[0093] In this design, the same tab has an overlapping portion in the first direction, that is, the tab is bent in the first direction, and the size of the tab in the first direction is reduced. Furthermore, in the same tab assembly, the number of intersections between all tabs and any straight line passing through the welding part along the first direction does not exceed the total number of all tabs. Therefore, the number of overlapping layers of all tabs in the tab assembly along the first direction does not exceed the number of tabs in the tab assembly. The size of the tab assembly along the first direction can be no greater than the thickness of a single tab multiplied by the number of tabs. Thus, the size of the tab assembly along the first direction can be reduced, thereby reducing the space occupied by the tab assembly in the height direction and improving the volumetric energy density of the battery cell.

[0094] The battery cells provided in this application embodiment can be used, but are not limited to, in battery devices. A battery device may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via busbars.

[0095] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0096] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0097] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0098] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0099] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0100] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0101] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0102] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0103] As an example, the battery cell can be a cylindrical battery, a prismatic battery, a pouch battery, or a battery of other shapes. Prismatic batteries include square-shell batteries, blade-shaped batteries, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0104] A single battery cell includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the negative and positive electrodes. During the charging and discharging process of the battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0105] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0106] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0107] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0108] As an example, the positive electrode active material layer may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active material layers in batteries may also be used. These positive electrode active material layers may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co The following are included: 0.25Mn0.25O2 (also known as NCM211), LiNi0.6Co0.2Mn0.2O2 (also known as NCM622), LiNi0.8Co0.1Mn0.1O2 (also known as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.8Co0.15Al0.05O2), and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned materials.

[0109] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not have a positive electrode active material layer. As an example, a positive electrode active material layer is filled and / or deposited within the foamed metal.

[0110] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0111] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0112] As an example, the negative electrode sheet may include a negative current collector and a layer of negative active material disposed on at least one surface of the negative current collector.

[0113] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0114] As an example, the negative electrode active material layer may employ a type of negative electrode active material layer known in the art for use in battery cells. As an example, the negative electrode active material layer may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active material layers in battery cells may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0115] In some embodiments, the negative electrode can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material layer, although a negative electrode active material layer may or may not be present.

[0116] As an example, a layer of negative electrode active material can be filled or / and deposited inside the negative electrode current collector.

[0117] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0118] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0119] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0120] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0121] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0122] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0123] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0124] In some implementations, the electrode assembly is a stacked structure.

[0125] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0126] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0127] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0128] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0129] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0130] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0131] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0132] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells or battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0133] The technical solutions described in the embodiments of this application are applicable to various energy storage devices that use battery cells or battery devices, such as energy storage containers or energy storage cabinets.

[0134] In the following embodiments, for ease of explanation, a vehicle 1000 is used as an example of an electrical device according to an embodiment of this application. The description is as follows with reference to the accompanying drawings.

[0135] Figure 1 This is a structural schematic diagram of a vehicle 1000 according to one or more embodiments.

[0136] Vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended vehicles, etc. For example... Figure 1 As shown, a battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0137] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0138] Figure 2 This is an exploded perspective view of a battery device 100 according to one or more embodiments.

[0139] like Figure 2 As shown, the battery device 100 includes a housing 10 and at least one battery cell 20. The housing 10 has a receiving space, in which at least one battery cell 20 is received.

[0140] In some embodiments of this application, the housing 10 may include a first housing 101 and a second housing 102. The first housing 101 and the second housing 102 are fastened together, forming an accommodating space inside the housing 10 to accommodate the battery cell 20. This accommodating space may be sealed or unsealed.

[0141] The second box 102 can be a hollow structure with one end open, and the first box 101 can be a plate-like structure. The first box 101 covers the open side of the second box 102 so that the first box 101 and the second box 102 together define the accommodating space. Alternatively, the first box 101 and the second box 102 can both be hollow structures with one side open, and the open side of the first box 101 covers the open side of the second box 102. Of course, the box 10 formed by the first box 101 and the second box 102 can be of various shapes, such as a cylinder, a cuboid, etc.

[0142] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of multiple battery cells 20 is placed in the receiving space formed by the second housing 102 and the first housing 101. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed in the receiving space formed by the second housing 102 and the first housing 101. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0143] Below, refer to Figures 3 to 21 Some embodiments of this application will be described in detail.

[0144] In some embodiments of this application, for ease of explanation, a first direction X, a second direction Y, and a third direction Z are defined, and the first direction X, the second direction Y, and the third direction Z intersect each other perpendicularly. For ease of explanation, as shown below... Figures 3 to 7 , Figure 10 , Figure 13 As shown by the arrows in the diagram, the direction of arrow X is the first direction, the direction of arrow Y is the second direction, and the direction of arrow Z is the third direction.

[0145] Figure 3 A three-dimensional structural schematic diagram of a battery cell according to one or more embodiments; Figure 4 This is a three-dimensional structural schematic diagram of an electrode assembly according to one or more embodiments; Figure 5 for Figure 4Sectional view at point AA; Figure 6 A front view of a first structure of an electrode assembly according to one or more embodiments; Figure 7 An exploded perspective view of a portion of the structure of a battery cell according to one or more embodiments; Figure 8 This is a three-dimensional structural schematic diagram of two adapter pieces according to one or more embodiments; Figure 9 A front view of the adapter piece according to one or more embodiments; Figure 10 A top view of a structure formed by welding multiple electrode assemblies with two adapter plates according to one or more embodiments; Figure 11 A three-dimensional structural schematic diagram of a first structure of multiple electrode assemblies according to one or more embodiments; Figure 12 This is a three-dimensional structural schematic diagram of a second structure of multiple electrode assemblies according to one or more embodiments; Figure 13 A front view of a second structure of an electrode assembly according to one or more embodiments; Figure 14 This is an exploded structural diagram of the end cap structure of a battery cell according to one or more embodiments. Figure 15 This is a three-dimensional structural diagram of the end cap structure of a battery cell according to one or more embodiments; Figure 16 A flowchart of a method for manufacturing a battery device according to one or more embodiments; Figure 17 This is a flowchart illustrating the manufacturing of an electrode assembly in a battery device manufacturing method according to one or more embodiments; Figure 18 This is a three-dimensional structural diagram of one aspect of the process of winding to form an electrode assembly according to one or more embodiments; Figure 19 This is a top view of another aspect of the process of winding to form an electrode assembly according to one or more embodiments; Figure 20 This is a front view of the positive electrode sheet in its unfolded state according to one or more embodiments; Figure 21 This is a front view of the negative electrode sheet in an unfolded state according to one or more embodiments.

[0146] The first aspect of this application provides a battery cell 20, such as Figures 3 to 6As shown, the battery cell 20 includes a housing 2, at least one terminal post assembly 3, and at least one electrode assembly 1. The housing 2 includes a shell 22 with an opening on one side along the first direction X and an end cap 21 that closes the opening. The end cap 21 and the shell 22 form a receiving cavity. The terminal post assembly 3 is disposed on the end cap 21. The electrode assembly 1 is disposed in the receiving cavity. The electrode assembly 1 includes a main body 16 and at least one tab assembly 14. The tab assembly 14 includes a plurality of tabs 141 that extend from the side of the main body 16 facing the end cap 21 and are stacked sequentially. At least a portion of the plurality of tabs 141 is welded to the terminal post assembly 3. The same tab 141 has an overlapping portion in the first direction X. In the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding part along the first direction X does not exceed the total number of all tabs 141.

[0147] The outer casing 2 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film. In some embodiments, the outer casing 2 can be a sealed structure or a non-sealed structure. As an example, when the outer casing 2 is a non-sealed structure, it serves to protect the electrode assembly 1, and a sealing bag is also included between the outer casing 2 and the electrode assembly 1. The sealing bag is used to encapsulate the electrode assembly 1 and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film. When the outer casing 2 is a sealed structure, it is used to encapsulate the electrode assembly 1 and electrolyte components. Exemplarily, the outer casing 2 can be cylindrical or prismatic. Prismatic shapes include square shells, blade shapes, and polygonal prisms, such as hexagonal prisms, etc., and this application does not have any particular limitations.

[0148] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength, so that end cap 21 is not easily deformed under pressure or impact, allowing battery cell 20 to have higher structural strength and improved safety performance. End cap 21 can also be provided with a pressure relief mechanism 6 for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. Pressure relief mechanism 6 can be, but is not limited to, an explosion-proof valve. The material of end cap 21 can also be various, such as copper, iron, aluminum, aluminum alloy, steel, titanium alloy, and copper alloy, etc., and this application embodiment does not impose special limitations on this. In some embodiments of this application, an insulating structure can also be provided on the inner side of end cap 21. The insulating structure can be used to isolate the electrical connection components inside housing 22 from end cap 21 to reduce the risk of short circuit. For example, the insulating structure can be made of plastic, rubber, etc.

[0149] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 1, electrolyte, and other components. The housing 22 and the end cap 21 are independent components. An opening is provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. The housing 22 can be of various shapes and sizes, such as cuboid, cube, cylinder, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 1. The housing 22 can be made of various materials, such as copper, iron, aluminum, aluminum alloy, plastic, steel, titanium alloy, and copper alloy, etc. This application embodiment does not impose any special limitations on these materials.

[0150] The tab assembly 14 is part of the electrode assembly 1 and is used to introduce current into the electrode assembly 1 or to extract current from the electrode assembly 1. At least one electrode assembly 1 may include a positive tab assembly 14a and / or a negative tab assembly 14b.

[0151] The electrode assembly 3 is a mechanical component connected to the tab 141 of the tab assembly 14 for introducing current into the electrode assembly 1 or discharging current from the electrode assembly 1. The electrode assembly 3 may include, but is not limited to, the electrode 31 and the adapter 32. At least one electrode assembly 3 may include a first electrode assembly 3a and / or a second electrode assembly 3b, wherein the first electrode assembly 3a is welded to the positive electrode tab assembly 14a, and the second electrode assembly 3b is welded to the negative electrode tab assembly 14b.

[0152] "The same tab 141 has an overlapping portion in the first direction X" means that the tab 141 does not extend in a straight line in the first direction X but is curved, such that a part of the tab 141 overlaps with another part of the tab 141 in the X direction.

[0153] "In the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding area along the first direction X does not exceed the total number of all tabs 141" means that the number of times all tabs 141 in the same tab assembly 14 are crossed by any straight line passing through the welding area along the first direction X is not less than the total number of all tabs 141 in the tab assembly 14. In other words, the number of overlaps of all tabs in the tab assembly along the first direction does not exceed the total number of all tabs 141 in the tab assembly 14. For example, if a tab 141 is bent and a straight line passes through the same tab 141 twice, the number of intersections between the straight line and the tab 141 is two. That is, when calculating the number of overlaps of all tabs along the first direction, the number of overlaps of this tab is counted as two.

[0154] It is understandable that "welding part" refers to the part where the tab assembly 14 is welded to the pole post assembly 3. In other words, it refers to the weld mark formed when the two are welded together on the tab assembly 14.

[0155] In the embodiments of this application, the same tab 141 has an overlapping portion in the first direction X, that is, the tab 141 is bent in the first direction X, and the size of the tab 141 in the first direction X is reduced; and, in the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding part along the first direction X does not exceed the total number of all tabs 141. Therefore, the number of overlapping layers of all tabs 141 in the tab assembly 14 along the first direction X does not exceed the number of tabs 141 in the tab assembly 14. The size of the tab assembly 14 along the first direction X can be no greater than the thickness of a single tab 141 multiplied by the number of tabs 141. Thus, the size of the tab assembly 14 along the first direction X can be reduced, thereby reducing the space occupied by the tab assembly 14 in the first direction X and improving the volumetric energy density of the battery cell 20.

[0156] In some embodiments of this application, such as Figures 3 to 6 As shown, the electrode assembly 1 has a wound structure. The main body 16 of the electrode assembly 1 includes a straight portion 161 and two corner portions 162 respectively provided at both ends of the straight portion 161 along the second direction Y. The stacking direction of the straight portion 161 is consistent with the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other. At least a portion of all the tabs 141 in the same tab assembly 14 extends from the same corner portion 162.

[0157] See Figure 5 In the figure, the part of the main body 16 located between the two dotted lines is the straight part 161, and the part located on the side where the two dotted lines are far apart is the corner part 162.

[0158] "At least a portion of all tabs 141 in the same tab assembly 14 extends from the same corner portion 162" indicates that the end of the tab assembly 14 connected to the main body 16 overlaps with the end face of the corner portion 162 corresponding to the tab assembly 14. For example, the end of the tab assembly 14 connected to the main body 16 completely covers the end face of the corner portion 162 corresponding to the tab assembly 14. Specifically, the tab assembly 14 may extend entirely from the corner portion 162; or the tab assembly 14 may extend partially from the corner portion 162, with the remaining portion extending from the straight portion 161. It is understood that the portions of the multiple tabs 141 constituting the tab assembly 14 extending from the corner portion 162 are stacked radially in the corner portion 162, and the portions extending from the straight portion 161 are stacked in the stacking direction (second direction Y) of the straight portion 161.

[0159] A tab 141 is provided at the corner 162 of the wound electrode assembly 1. Since the corner 162 is semi-circular in the cross section perpendicular to the first direction X, the multiple layers of tabs 141 constituting the tab assembly 14 are arranged in sequence, which helps to improve the interaction force between the tabs 141. Furthermore, the tabs 141 have overlapping portions in the first direction X, which allows adjacent tabs 141 to be in close contact with each other, forming a compact tab assembly 14. This not only facilitates the welding operation between the tab assembly 14 and the electrode post assembly 3, but also allows the size of the tabs 141 along the first direction X to be relatively small.

[0160] In some embodiments of this application, such as Figures 3 to 5 As shown, the electrode assembly 1 is formed by winding a laminate including a positive electrode 11 and a negative electrode 12. A spacer 13 is sandwiched between the positive electrode 11 and the negative electrode 12. At least one tab assembly 14 includes a positive tab assembly 14a. The portion of the positive electrode 11 near the end cap 21 that extends beyond the spacer 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the positive electrode 11 are stacked sequentially to form the positive tab assembly 14a. And / or, at least one tab assembly 14 includes a negative tab assembly 14b. The portion of the negative electrode 12 near the end cap 21 that extends beyond the spacer 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the negative electrode 12 are stacked sequentially to form the negative tab assembly 14b.

[0161] Electrode assembly 1 is the component in the battery cell 20 where electrochemical reactions occur. The housing 2 may contain one or more electrode assemblies 1. Exemplarily, electrode assembly 1 includes a positive electrode 11, a negative electrode 12, and a separator 13 disposed between the negative electrode 12 and the positive electrode 11. During the charging and discharging process of the battery cell 20, active ions (e.g., lithium ions) repeatedly insert and extract between the positive electrode 11 and the negative electrode 12. The separator 13, disposed between the positive electrode 11 and the negative electrode 12, can reduce the risk of short circuits between the positive and negative electrodes while allowing active ions to pass through. The positive electrode 11 includes a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector. A positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode current collector portion and a positive electrode protrusion portion protruding from the positive electrode current collector portion. The positive electrode current collector portion is coated with a positive electrode active material layer, and at least a portion of the positive electrode protrusion portion is not coated with a positive electrode active material layer. At least a portion of the positive electrode protrusion portion extends beyond the separator 13, and the extended portion serves as a positive electrode tab. Multiple positive electrode tabs are stacked to form a positive electrode tab assembly 14a. The negative electrode 12 includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector. The negative active material layer is coated on the surface of the negative current collector. The negative current collector includes a negative current collection portion and a negative current convex portion protruding from the negative current collection portion. The negative current collection portion is coated with the negative active material layer, and at least a portion of the negative current convex portion is not coated with the negative active material layer. At least a portion of the negative current convex portion extends beyond the separator 13, and the extended portion serves as a negative electrode tab. Multiple negative electrode tabs are stacked to form a negative electrode tab assembly 14b. The positive current collection portion, the portion of the positive current convex portion that does not extend beyond the separator 13, the negative current collection portion, the portion of the negative current convex portion that does not extend beyond the separator 13, and the separator 13 are stacked and wound together to form the main body portion 16 of the electrode assembly 1. It is understood that the positive electrode tab constituting the positive electrode tab assembly 14a is at least a portion of the positive current convex portion, and the negative electrode tab constituting the negative electrode tab assembly 14b is at least a portion of the negative current convex portion. Both the positive electrode tab and the negative electrode tab are referred to as electrode tab 141.

[0162] For example, the entire positive electrode tab assembly 14a extends from the corner portion 162 corresponding to the positive electrode tab assembly 14a, that is, the end of the positive electrode tab assembly 14a connected to the main body portion 16 does not overlap with the end face of the straight portion 161; the entire negative electrode tab assembly 14b extends from the corner portion 162 corresponding to the negative electrode tab assembly 14b, that is, the end of the negative electrode tab assembly 14b connected to the main body portion 16 does not overlap with the end face of the straight portion 161.

[0163] For example, such as Figure 4As shown, part of the positive electrode tab assembly 14a extends from its corresponding corner portion 162, and another part extends from the straight portion 161. That is, the end of the positive electrode tab assembly 14a that connects to the main body portion 16 overlaps with the end face of the straight portion 161. Part of the negative electrode tab assembly 14b extends from its corresponding corner portion 162, and another part extends from the straight portion 161. That is, the end of the negative electrode tab assembly 14b that connects to the main body portion 16 overlaps with the end face of the straight portion 161.

[0164] For example, each turn of the positive electrode 11 has a tab 141 (positive electrode tab) extending out. That is, the number of turns of the positive electrode 11 is equal to the number of layers of tabs 141 in the positive electrode tab assembly 14a. This is more conducive to improving the tightness of contact between the tabs 141 in the positive electrode tab assembly 14a, reducing contact resistance, improving conductivity, and also improving the mechanical strength of the overall structure of the positive electrode tab assembly 14a, reducing the risk of short circuit caused by mechanical damage. Similarly, each turn of the negative electrode sheet 12 has a tab 141 (negative electrode tab) extending out. That is, the number of turns of the negative electrode sheet 12 is equal to the number of layers of tabs 141 in the negative electrode tab assembly 14b. This is more conducive to improving the tightness of contact between the tabs 141 in the negative electrode tab assembly 14b, reducing contact resistance, improving conductivity, and also improving the mechanical strength of the overall structure of the negative electrode tab assembly 14b, reducing the risk of short circuit caused by mechanical damage.

[0165] For example, the positive electrode 11 does not have tabs 141 (positive electrode tabs) in the first N turns of winding, but tabs 141 (positive electrode tabs) extend in each turn from N+1 onwards. Similarly, the negative electrode 12 does not have tabs 141 (negative electrode tabs) in the first M turns of winding, but tabs 141 (negative electrode tabs) extend in each turn from M+1 onwards. The N and M turns can be, but are not limited to, two, three, or four turns. This is because the thickness is very small at the beginning of winding, and the tabs 141 at the corners are relatively short along the winding direction C, making them prone to burrs. Therefore, not extending tabs 141 in the first few turns reduces burr formation.

[0166] Thus, a wound electrode assembly 1 is formed by winding the positive electrode 11, the negative electrode 12 and the separator 13, and the size of the tab 141 of the electrode assembly 1 along the first direction X can be reduced, thereby reducing the space occupied by the tab 141 in the first direction X and increasing the volumetric energy density of the battery cell 20.

[0167] In some embodiments of this application, such as Figure 4 and Figure 6As shown, the electrode assembly 1 has a wound structure. The main body 16 of the electrode assembly 1 includes a straight part 161 and two corner parts 162 respectively provided at both ends of the straight part 161 along the second direction Y. The stacking direction of the straight part 161 is consistent with the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other. The ratio of the size H1 of the tab 141 along the first direction X to the size H2 of the electrode assembly 1 along the third direction Z is between 0.125 and 0.15.

[0168] For example, the ratio of the dimension H1 of the tab 141 along the first direction X to the dimension H2 of the electrode assembly 1 along the third direction Z can be, but is not limited to, 0.125, 0.126, 0.127, 0.128, 0.129, 0.13, 0.131, 0.132, 0.133, 0.134, 0.135, 0.136, 0.137, 0.138, 0.139, 0.14, 0.141, 0.142, 0.143, 0.144, 0.145, 0.146, 0.147, 0.148, 0.149, and 0.15.

[0169] Thus, by setting the ratio of the dimension H1 of the tab 141 along the first direction X to the dimension H2 of the electrode assembly 1 along the third direction Z in the range of 0.125 to 0.15, the height of the tab 141 (the dimension H1 along the first direction X) is relatively small, which is beneficial to improving the volumetric energy density of the battery cell 20. Furthermore, the height of the tab 141 is not so small that it would affect the welding with the electrode assembly 3.

[0170] In some embodiments of this application, such as Figure 6 As shown, along the first direction X, the size H1 of the tab 141 is in the range of 0.5mm to 1.5mm.

[0171] For example, along the first direction X, the size H1 of the tab 141 can be, but is not limited to, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm.

[0172] Thus, by setting the size of the tab 141 along the first direction X to be in the range of 0.5mm to 1.5mm, the size of the tab 141 along the first direction X is significantly reduced, thereby reducing the space occupied in the first direction X, increasing the volumetric energy density of the battery cell 20, and the above-mentioned size range reduces the probability that the tab 141 is too small and will penetrate into the main body 16 and burn the separator 13 when welding it to the electrode assembly 3, thereby reducing the risk of short circuit of the electrode assembly 1.

[0173] In some embodiments of this application, such as Figure 4As shown, the dimension H2 of electrode assembly 1 along the third direction Z is in the range of 10mm to 40mm.

[0174] For example, the dimension H2 of the electrode assembly 1 along the third direction Z can be, but is not limited to, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, or 40mm.

[0175] In some embodiments of this application, the electrode assembly 14, which includes a plurality of sequentially stacked electrodes 141, is formed by a flattening process.

[0176] After the electrode assembly 1 undergoes winding and shaping (flattening) processes, the tabs 141 of the same polarity are stacked. At this time, the tabs 141 extend along the first direction X and have no overlapping portion in the first direction X. In this embodiment, the tabs 141 can be bent by a flattening process, resulting in overlapping portions in the first direction X, so that multiple layers of tabs 141 overlap together in the first direction X. The flattening process can be to press the multiple layers of tabs from top to bottom along a straight direction, so that the multiple layers of tabs are in close contact with each other; the flattening process can also be to rotate and press the multiple layers of stacked tabs from top to bottom along a spiral direction, so that the multiple layers of tabs are in close contact with each other to form the tab assembly 14.

[0177] In some embodiments of this application, such as Figure 3 As shown, electrode assembly 1 has two or more electrodes arranged sequentially along the third direction Z.

[0178] The capacity of the battery cell 20 is increased by setting two or more electrode assemblies 1 inside the casing 2.

[0179] In some embodiments of this application, a solder mark is formed on the end face of the pole assembly 3 facing away from the receiving cavity.

[0180] For example, such as Figure 3 As shown, the pole assembly 3 includes a pole 31 disposed on the end cap 21 and an adapter piece 32 connected to the surface of the pole 31 facing the receiving cavity. The adapter piece 32 is welded to the tab 141.

[0181] like Figure 3 As shown in the figure, the shaded area on the upper surface of the pole post 31 represents the solder mark formed on the end face of the pole post assembly 3 facing away from the receiving cavity.

[0182] It is understood that the weld mark formed on the outer end face of the pole assembly 3 indicates that the pole assembly 3 and the tab 141 are welded together by a through weld from the outside to the inside of the housing 2. Exemplary welding methods may include, but are not limited to, laser welding.

[0183] In this way, the metal impurities generated during welding are on the outside and will not enter the inside, which reduces the risk of short circuits caused by metal impurities piercing the separator 13. Moreover, welding from the outside simplifies the assembly process of the battery cell 20 and helps to improve production efficiency.

[0184] In some embodiments of this application, such as Figure 7 As shown, the pole assembly 3 includes a pole 31, which is directly welded to the tab 141.

[0185] Thus, by directly connecting the pole post 31 and the tab 141, the space occupied in the first direction X is further reduced, and the volumetric energy density is increased.

[0186] In some embodiments of this application, such as Figure 7 As shown, the battery cell 20 also includes an insulating member 5, which is supported between the main body 16 and the end cap 21. The insulating member 5 has a through hole 51, through which all the tabs 141 of the same tab assembly 14 pass and at least some of the tabs 141 are welded to the terminal post 31.

[0187] For example, the material of the insulating element 5 may be any one or more of polypropylene, polyethylene, polyimide, polyvinyl chloride, ethylene-vinyl acetate copolymer, and silicone foam, including but not limited to.

[0188] For example, the through hole 51 is adapted to the shape and size of the tab assembly 14, that is, the inner wall of the through hole 51 is adapted to the outer peripheral surface of the tab assembly 14, so that the inner wall of the through hole 51 is in contact with the outer peripheral surface of the tab assembly 14 or has a set gap. The set gap is within a relatively small size range, and the specific value range is not specifically limited here.

[0189] For example, such as Figure 7 As shown, two or more electrode assemblies 1 are arranged sequentially along the third direction Z, and the insulating member 5 forms two or more through holes 51 that penetrate along the first direction X. Multiple through holes 51 of the same insulating member 5 pass through multiple tab assemblies 14 in a one-to-one correspondence.

[0190] Thus, the electrode post 31 and the tab 141 are directly connected, further reducing the space occupied in the first direction X and further improving the volumetric energy density of the battery cell 20. By providing the insulating member 5 between the main body 16 and the end cap 21 of the electrode assembly 1, the probability of electrical conduction between the end cap 21 and the main body 16 can be reduced, lowering the risk of short circuits. Furthermore, the supporting effect of the insulating member 5 improves the structural stability of the tab assembly 14. In addition, the inner wall of the through hole 51 limits the outer periphery of the tab assembly 14, reducing the probability of the tab 141 of the tab assembly 14 spreading outwards when welding is performed by applying pressure to the electrode post 31 from the outside, thus helping to maintain the shape of the tab assembly 14 and improving its conductivity.

[0191] In some embodiments of this application, such as Figure 7 As shown, the pole post 31 includes a body part 311. The outer surface of the body part 311 has a plurality of protrusions 312 protruding to one side of the receiving cavity. The inner side of the body part 311 and the plurality of protrusions 312 are respectively welded to a plurality of pole tab assemblies 14 in a first direction X.

[0192] The protrusion 312 protrudes outward relative to the body portion 311, making it easy to connect to conductive components such as busbars. Furthermore, multiple protrusions 312 correspond one-to-one with multiple tab assemblies 14 in the first direction X, thereby increasing the current flow area between the terminal post 31 and the tab assembly 14 and improving charging and discharging efficiency.

[0193] In some embodiments of this application, such as Figure 7 As shown, the tab assembly 14 is welded to the pole post 31, and a solder mark is formed on the surface of the pole post 31 facing away from the receiving cavity.

[0194] It should be noted that, Figure 7 The shaded area on the upper surface of the middle pole 31 is the weld mark formed by welding the tab assembly 14 to the pole 31 on the surface of the pole 31 facing away from the receiving cavity.

[0195] Understandably, the surface of the pole post 31 facing away from the receiving cavity has solder marks, indicating that the tab assembly 14 and the pole post 31 are welded together by through-welding from the outside to the inside of the housing 2. Exemplary welding methods may include, but are not limited to, laser through-welding.

[0196] In this way, the metal impurities generated during welding are on the outside and will not enter the inside, which reduces the risk of short circuits caused by metal impurities piercing the separator 13. Moreover, welding from the outside simplifies the assembly process of the battery cell 20 and helps to improve production efficiency.

[0197] In some embodiments of this application, such as Figure 3As shown, the pole assembly 3 includes a pole 31 and an adapter plate 32. The pole 31 is disposed on the end cap 21, and the adapter plate 32 is disposed in the receiving cavity. The end of the pole 31 facing the receiving cavity is welded to the adapter plate 32, and the adapter plate 32 is welded to the tab 141.

[0198] The connection is simplified by welding the adapter piece 32. Moreover, the adapter piece 32 makes it easy to electrically connect multiple tab assemblies 14 to the same pole post 31, simplifying the operation.

[0199] In some embodiments of this application, such as Figure 3 As shown, there are two or more electrode assemblies 1 arranged sequentially along the third direction Z. The electrode tabs 14 of the same polarity of each electrode assembly 1 are connected to the same adapter plate 32, and the adapter plate 32 is connected to the pole post 31.

[0200] In this way, multiple tab assemblies 14 and terminals 31 can be connected through the same adapter piece 32, which helps to simplify the connection operation and improve the production efficiency of battery cells.

[0201] In some embodiments of this application, such as Figure 3 and Figure 9 As shown, the surface of the adapter piece 32 facing away from the end cap 21 is the first plane 321, and the adapter piece 32 is welded to the tab 141 through the first plane 321.

[0202] By setting the surface of the adapter plate 32 facing away from the end cap 21 as a plane, which is connected to the tab 141, the distance between the adapter plate 32 and the main body 16 of the electrode assembly 1 is equal to the size of the tab 141 along the first direction X. This makes the distance between the adapter plate 32 and the main body 16 smaller, reducing the occupancy of the cavity and increasing the volumetric energy density of the battery cell 20.

[0203] In some embodiments of this application, such as Figure 3 , Figure 8 and Figure 9 As shown, the surface of the adapter piece 32 facing the end cap 21 is the second plane 322, and the adapter piece 32 is welded to the pole post 31 through the second plane 322.

[0204] Thus, the adapter plate 32 has a flat plate structure, which is simple in structure and molding process, reducing manufacturing costs. In addition, it helps to further reduce the space occupied in the first direction X, and further improve the volumetric energy density of the battery cell 20.

[0205] For example, the adapter plate 32 may be made of, but is not limited to, copper or aluminum.

[0206] In some embodiments of this application, such as Figure 10As shown, the edge of the adapter piece 32 corresponding to the positive electrode tab assembly 14a near the negative electrode tab assembly 14b does not extend beyond the positive electrode tab assembly 14a along the second direction Y; the edge of the adapter piece 32 corresponding to the negative electrode tab assembly 14b near the positive electrode tab assembly 14a does not extend beyond the negative electrode tab assembly 14b along the second direction Y.

[0207] For example, such as Figure 10 As shown in the figure, the shaded area represents the end face of the tab assembly 14 facing the end cover 21. The edge of the adapter piece 32 corresponding to the positive tab assembly 14a near the negative tab assembly 14b is aligned with the edge of the positive tab assembly 14a in the first direction X (viewed along the first direction X). The edge of the adapter piece 32 corresponding to the negative tab assembly 14b near the positive tab assembly 14a is aligned with the edge of the negative tab assembly 14b in the first direction X (viewed along the first direction X).

[0208] This configuration allows for a reduction in the size of the adapter plate 32, saving material costs. Furthermore, the tab assembly 14, positioned between the main body 16 and the adapter plate 32, reduces the risk of a short circuit caused by contact between the adapter plate 32 and the opposite polarity electrode in the main body 16. This allows for a smaller spacing between the adapter plate 32 and the main body 16, which is beneficial for increasing volumetric energy density.

[0209] In some embodiments of this application, such as Figure 9 As shown, the maximum thickness L of the adapter piece 32 is in the range of 0.8mm to 1.5mm.

[0210] For example, the maximum thickness L of the adapter piece 32 can be, but is not limited to, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm.

[0211] In this way, by setting the thickness of the adapter piece 32 within a relatively thin range, multiple tab assemblies 14 can be indirectly connected to the same pole post 31, without affecting the volumetric energy density of the battery cell 20 due to excessive thickness.

[0212] In some embodiments of this application, such as Figure 3 As shown, the pole post 31, adapter plate 32, and tab 141 are integrally welded. The integral welding of tab 141, adapter plate 32, and pole post 31 is a process that connects these three components into a single unit in one step. This integral welding improves welding efficiency.

[0213] In some embodiments of this application, such as Figure 3 , Figure 8 and Figure 11 As shown, a solder mark is formed on the end face of the pole 31 facing away from the receiving cavity.

[0214] like Figure 3 As shown, the shaded area on the upper surface of pole 31 indicates the solder mark formed thereon.

[0215] like Figure 8 As shown, the shaded area on the upper surface of the adapter piece 32 indicates the solder marks formed thereon.

[0216] like Figure 11 As shown, the shaded portion on the upper surface of the tab assembly 14 indicates the solder marks formed thereon.

[0217] Understandably, the surface of the pole 31 facing away from the receiving cavity has solder marks, indicating that the tab assembly 14, the adapter piece 32, and the pole 31 are welded by through-welding from the outside to the inside of the housing 2. Exemplary welding methods may include, but are not limited to, laser welding.

[0218] Metal impurities generated by the external penetration welding remain on the outside of the casing 2 and will not enter the inside, thus reducing the risk of short circuits caused by metal impurities piercing the separator 13. Moreover, the external welding method simplifies the assembly process of the battery cells 20, which helps to improve production efficiency.

[0219] In some embodiments of this application, such as Figure 11 and Figure 12 As shown, the tab assembly 14 is welded to the pole assembly 3, and a solder mark is formed on a portion of the end face of the tab assembly 14 facing the end cover 21.

[0220] See Figure 11 and Figure 12 The shaded area on the end face of the tab assembly 14 indicates the solder marks formed thereon.

[0221] Because the tabs 141 of the tab assembly 14 are in close contact with each other and have strong conductivity, the end face of the tab assembly 14 can be welded to the pole assembly 3 to meet the conductivity requirements. In addition, this arrangement also saves the energy required for welding.

[0222] Of course, it is understandable that the size of the solder mark is not limited to this; it is also possible that the entire end face of the tab assembly 14 is covered with solder marks.

[0223] In some embodiments of this application, such as Figure 12 As shown, the electrode assembly 1 also includes at least one boss 15 adjacent to the tab assembly 14. The boss 15 includes a plurality of sheets 151 that extend from the side of the main body portion 16 facing the end cap 21 and are stacked in sequence. Along the first direction X, the size of the sheets 151 is smaller than the size of the tab 141.

[0224] For example, the portion of the positive electrode 11 extending beyond the separator 13 near the end cap 21 further includes a plurality of sheets 151 arranged sequentially at intervals along the winding direction C. The plurality of sheets 151 are stacked to form a boss 15, which is connected to the positive electrode tab assembly 14a. Similarly, the portion of the negative electrode 12 extending beyond the separator 13 near the end cap 21 further includes a plurality of sheets 151 arranged sequentially at intervals along the winding direction C. The plurality of sheets 151 are stacked to form another boss 15, which is connected to the negative electrode tab assembly 14b.

[0225] For example, the boss 15 connected to the positive electrode tab assembly 14a is located on the side of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b, and the boss 15 connected to the negative electrode tab assembly 14b is located on the side of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a.

[0226] When performing operations such as flattening the tab 141, which cause the tab 141 to bend, the tab 141 is prone to shedding debris. That is, debris is likely to be generated near the tab 141. Therefore, a boss 15 is provided near the tab 141 to prevent debris from entering the main body 16 and piercing the isolation member 13, thereby reducing the risk of short circuit.

[0227] In some embodiments of this application, such as Figure 11 and Figure 12 As shown, the solder marks formed on the end face of the tab assembly 14 facing the end cap 21 are fan-shaped, circular, or square.

[0228] Circular solder marks distribute stress evenly during welding, reducing localized stress concentration and lowering the risk of solder joint cracking. Square solder marks achieve a larger effective contact area, significantly reducing internal resistance. Fan-shaped solder marks can conform to curved distributions, making them suitable for tab assemblies 14 with semi-circular cross-sections, improving welding yield.

[0229] In some embodiments of this application, such as Figure 11 and Figure 12 As shown, at least one electrode assembly 14 includes a positive electrode assembly 14a and a negative electrode assembly 14b. The electrode 141 of the positive electrode assembly 14a is a positive electrode, and the electrode 141 of the negative electrode assembly 14b is a negative electrode. The positive electrode assembly 14a is connected to a corner portion 162, and the negative electrode assembly 14b is connected to another corner portion 162.

[0230] Thus, the two corner portions 162 are respectively connected to the positive electrode tab and the negative electrode tab, making the distance between the positive electrode tab and the negative electrode tab larger, reducing the risk of short circuit, and making the structure of the positive electrode tab assembly 14a and the negative electrode tab assembly 14b compact, allowing the dimensions of the two along the first direction X to be relatively small.

[0231] In some embodiments of this application, such as Figure 3 As shown, at least one electrode assembly 3 includes a first electrode assembly 3a and a second electrode assembly 3b. The first electrode assembly 3a is welded to the positive electrode tab assembly 14a, and the second electrode assembly 3b is welded to the negative electrode tab assembly 14b.

[0232] Thus, the arrangement of the first terminal assembly 3a and the second terminal assembly 3b facilitates the connection of the positive electrode tab assembly 14a and the negative electrode tab assembly 14b with conductive components such as the busbar, so that the current of the battery cell 20 is discharged through the first terminal assembly 3a and the current is introduced through the second terminal assembly 3b.

[0233] In some embodiments of this application, such as Figure 7 As shown, the outer peripheral surface of the tab assembly 14 includes at least one first side surface 142, and the outer peripheral surface of the tab assembly 14 is disposed around a central axis extending in a first direction X of the tab assembly 14, and the at least one first side surface 142 includes a plane.

[0234] This makes at least one side of the tab assembly 14 flat, resulting in a neat structure of the tab assembly 14, which helps to improve the structural strength of the tab assembly 14, and also facilitates the cutting of the tab 141.

[0235] In some embodiments of this application, such as Figure 7 As shown, the first side 142 extends obliquely from one end connected to the main body 16 to the end away from the main body 16 towards the side closer to the central axis.

[0236] This design reduces the risk of cracking between the tab 141 and the main body 16 during operations that cause the tab 141 to bend, such as kneading.

[0237] In some embodiments of this application, such as Figure 13 As shown, the first side 142 is parallel to the first direction X. This arrangement eliminates the need for multiple orientation adjustments during electrode cutting, thus reducing material waste.

[0238] In some embodiments of this application, such as Figure 13 As shown, an arc-shaped surface 143 is formed at the connection between the first side surface 142 and the end face of the main body 16.

[0239] In this way, at least one side of the tab assembly 14 and the end face of the main body 16 are connected by an arc surface 143, which improves the connection reliability between the two and reduces the risk of cracking between the tab 141 and the main body 16 during the bending of the tab 141.

[0240] In some embodiments of this application, such as Figure 13As shown, the surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b is parallel to the first direction X; and / or, the surface of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a is parallel to the first direction X.

[0241] For example, the surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b is a first side surface 142, which is parallel to the first direction X. The surface of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a is also a first side surface 142, which is parallel to the first direction X.

[0242] This design eliminates the need for repeated orientation adjustments during electrode cutting, thus reducing material waste.

[0243] In some embodiments of this application, such as Figure 6 As shown, the surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b extends obliquely from one end of the connecting body portion 16 to the end away from the body portion 16 towards the side away from the negative electrode tab assembly 14b; and / or, the surface of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a extends obliquely from one end of the connecting body portion 16 to the end away from the body portion 16 towards the side away from the positive electrode tab assembly 14a.

[0244] Understandably, see Figure 6 The surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b is a first side surface 142. This first side surface 142 extends obliquely from one end connected to the main body portion 16 to the end away from the main body portion 16, moving away from the negative electrode tab assembly 14b. The positive electrode tab assembly 14a gradually decreases in size in the second direction Y from the end near the main body portion 16 to the end away from the main body portion 16. The positive electrode tab assembly 14a is generally a right-angled trapezoid in its orthographic projection along the third direction Z. See, for example... Figure 6 The angle θ between the first side 142 and the first direction X can be, but is not limited to, 10°, 20°, 15°, 30°, 40°, 45°, or 60°. The structure of the negative electrode tab assembly 14b is similar to that of the positive electrode tab assembly 14a, and will not be described in detail here.

[0245] This design reduces the risk of cracking between the tab 141 and the main body 16 during operations that cause the tab 141 to bend, such as kneading.

[0246] In some embodiments of this application, such as Figure 6 and Figure 13As shown, an arc-shaped surface 143 is formed at the connection between the surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b and the end face of the main body 16; and / or, an arc-shaped surface 143 is formed at the connection between the surface of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a and the end face of the main body 16.

[0247] For example, the surface of the positive electrode tab assembly 14a facing the negative electrode tab assembly 14b is a first side surface 142, and the surface of the negative electrode tab assembly 14b facing the positive electrode tab assembly 14a is also a first side surface 142. An arc-shaped surface 143 is formed at the connection between the two first side surfaces 142 and the end face of the main body 16.

[0248] In this way, the surface of the tab assembly 14 and the end face of the main body 16 are transitioned by the arc surface 143, which improves the connection reliability between the two and reduces the risk of cracking between the tab 141 and the main body 16 during operations such as flattening that cause the tab 141 to bend.

[0249] In some embodiments of this application, such as Figure 14 As shown, the end cap 21 has a first pole mounting hole 211 and a second pole mounting hole 212. The first pole 31a and the second pole 31b are respectively installed in the first pole mounting hole 211 and the second pole mounting hole 212. The first pole 31a and the second pole 31b are both poles 31. A first upper plastic 71 is sandwiched between the first pole 31a and the first pole mounting hole 211, and a second upper plastic 72 is sandwiched between the second pole 31b and the second pole mounting hole 212. A lower plastic 73 is provided on the surface of the end cap 21 facing the receiving cavity.

[0250] In some embodiments of this application, such as Figure 15 As shown, the inner surface of the first pole post 31a has a first groove 313 recessed toward the side opposite to the receiving cavity, and the inner surface of the second pole post 31b has a second groove 314 recessed toward the side opposite to the receiving cavity.

[0251] For example, the first groove 313 is used to accommodate a portion of an adapter piece 32, the portion of which extends into the first groove 313 is connected to the first terminal 31a, and the portion of which is outside the first groove 313 is connected to the positive electrode assembly 14a. The second groove 314 is used to accommodate a portion of another adapter piece 32, the portion of which extends into the second groove 314 is connected to the second terminal 31b, and the portion of which is outside the second groove 314 is connected to the negative electrode assembly 14b.

[0252] For example, the first groove 313 is used to accommodate at least a portion of each positive electrode tab assembly 14a, and the portion of each positive electrode tab assembly 14a extending into the first groove 313 is connected to the first terminal post 31a. The second groove 314 is used to accommodate at least a portion of each negative electrode tab assembly 14b, and the portion of each negative electrode tab assembly 14b extending into the second groove 314 is connected to the second terminal post 31b.

[0253] Thus, by forming grooves (first groove 313 and second groove 314) on the surface of the pole post 31 facing the receiving cavity, the portion of the adapter piece 32 or the portion of the tab assembly 14 connected to the pole post 31 fits into the groove, thereby improving the mutual limiting effect between the adapter piece 32 or the tab assembly 14 and the pole post 31, which is beneficial to improving the welding quality.

[0254] The second aspect of this application provides a battery device 100, which includes a plurality of battery cells 20 provided in the first aspect.

[0255] Because the battery cell 20 provided in the first aspect has a high volumetric energy density, the battery device 100 including a plurality of battery cells 20 provided in the first aspect has a high volumetric energy density.

[0256] A third aspect of this application provides an energy storage device, which includes a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect, wherein the battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0257] Since the battery cell 20 provided in the first aspect has a high volumetric energy density and the battery device 100 provided in the second aspect has a high volumetric energy density, the energy storage device including a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect has a high volumetric energy density.

[0258] The fourth aspect of this application provides an electrical device that includes a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect, wherein the battery cells 20 or battery devices 100 are used to store or provide electrical energy.

[0259] Since the battery cell 20 provided in the first aspect has a high volumetric energy density and the battery device 100 provided in the second aspect has a high volumetric energy density, the power-consuming device including a plurality of battery cells 20 provided in the first aspect or a plurality of battery devices 100 provided in the second aspect has a high volumetric energy density.

[0260] The fifth aspect of this application provides a method for manufacturing a battery cell 20, such as... Figure 16 As shown, the manufacturing method includes:

[0261] S1. Provides a housing, end caps, and at least one pole post assembly.

[0262] The housing 22 has an opening on one side along the first direction X;

[0263] S2. Install the pole assembly onto the end cap;

[0264] S3. Fabricate electrode components.

[0265] The electrode assembly includes a main body and at least one tab assembly. The tab assembly includes a plurality of tabs that extend from one side of the main body 16 and are stacked sequentially.

[0266] S4. Place the electrode assembly into the housing;

[0267] S5. Seal the opening with the end cap;

[0268] S6. Weld at least a portion of the multiple tabs of the pole post assembly to the tab assembly;

[0269] Among them, the same tab 141 has an overlapping portion in the first direction X, and in the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding part along the first direction X does not exceed the total number of all tabs 141.

[0270] In the embodiments of this application, the same tab 141 has an overlapping portion in the first direction X, that is, the tab 141 is bent in the first direction X, and the size of the tab 141 in the first direction X is reduced; and, in the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding part along the first direction X does not exceed the total number of all tabs 141. Therefore, the number of overlapping layers of all tabs 141 in the tab assembly 14 along the first direction X does not exceed the number of tabs 141 in the tab assembly 14. The size of the tab assembly 14 along the first direction X can be no greater than the thickness of a single tab 141 multiplied by the number of tabs 141. Thus, the size of the tab assembly 14 along the first direction X can be reduced, thereby reducing the space occupied by the tab assembly 14 in the first direction X and improving the volumetric energy density of the battery cell 20.

[0271] In some embodiments of this application, such as Figure 17 As shown, electrode assembly 1 is fabricated, including:

[0272] S31. Provide positive electrode plates, negative electrode plates and insulating components;

[0273] S32. The positive electrode sheet, negative electrode sheet, and separator are stacked and wound to form a wound structure.

[0274] The portion of the positive electrode 11 extending beyond the separator 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the positive electrode 11 are stacked to form a first stacked structure. The portion of the negative electrode 12 extending beyond the separator 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the negative electrode 12 are stacked to form a second stacked structure.

[0275] S33. The first layered structure is flattened to form a positive electrode tab assembly, and the second layered structure is flattened to form a negative electrode tab assembly, so that the wound structure is formed into an electrode assembly.

[0276] Among them, the positive electrode tab assembly 14a and the negative electrode tab assembly 14b are both tab assemblies 14.

[0277] The flattening process makes the tab assembly 14 form a compact structure, which helps to reduce the height of the tab assembly 14 and simplifies the welding process with the pole assembly 3.

[0278] In some embodiments of this application, after step S33, multiple electrode assemblies 1 are arranged and connected in sequence.

[0279] It is understandable that each electrode assembly 1 is formed first, and then multiple electrode assemblies 1 are grouped together.

[0280] In some embodiments of this application, between step S32 and step S33, the manufacturing method further includes: arranging and connecting multiple wound structural members sequentially.

[0281] Understandably, multiple wound structural components are first connected together, and then the overall structure formed by connecting the multiple wound structural components is flattened to form multiple electrode assemblies 1 arranged in sequence. This helps to improve production efficiency.

[0282] The following describes specific examples of some embodiments of this application with reference to the accompanying drawings.

[0283] As a specific example, a battery cell 20 is provided. The battery cell 20 includes a housing 2, at least one terminal post assembly 3, and at least one electrode assembly 1. The housing 2 includes a shell 22 with an opening on one side along a first direction X and an end cap 21 that closes the opening. The end cap 21 and the shell 22 form a receiving cavity. The terminal post assembly 3 is disposed on the end cap 21. The electrode assembly 1 is disposed in the receiving cavity. The electrode assembly 1 includes a main body 16 and at least one tab assembly 14. The tab assembly 14 includes a plurality of tabs 141 extending from the side of the main body 16 facing the end cap 21 and stacked sequentially. At least a portion of the plurality of tabs 141 is welded to the terminal post assembly 3. The same tab 141 has an overlapping portion in the first direction X. In the same tab assembly 14, the number of intersections between all tabs 141 and any straight line passing through the welding part along the first direction X does not exceed the total number of all tabs 141. The dimension H1 of the electrode assembly 1 along the first direction X is in the range of 0.5 mm to 1.5 mm. Electrode assembly 1 is formed by winding a laminate including a positive electrode 11 and a negative electrode 12. A spacer 13 is sandwiched between the positive electrode 11 and the negative electrode 12. At least one tab assembly 14 includes a positive tab assembly 14a. The portion of the positive electrode 11 near the end cap 21 that extends beyond the spacer 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the positive electrode 11 are stacked sequentially to form the positive tab assembly 14a. At least one tab assembly 14 includes a negative tab assembly 14b. The portion of the negative electrode 12 near the end cap 21 that extends beyond the spacer 13 includes a plurality of tabs 141 arranged sequentially and spaced apart along the winding direction. The plurality of tabs 141 of the negative electrode 12 are stacked sequentially and spaced apart along the winding direction. The negative electrode tab assembly 14b is formed by stacking the positive electrode 11 (the portion not exceeding the separator 13) and the negative electrode 12 (the portion not exceeding the separator 13) together and wound to form the main body 16. The main body 16 is flat in shape. The two bends of the main body 16 are corner portions 162 and the straight portion of the main body 16 is a straight portion 161. The two corner portions 162 are respectively provided at both ends of the straight portion 161 along the second direction Y. The stacking direction of the straight portion 161 is consistent with the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other. At least a portion of the positive electrode tab assembly 14a extends from one corner portion 162 and the negative electrode tab assembly 14b extends from the other corner portion 162.

[0284] The pole assembly 3 includes a pole 31, which is welded to the tab assembly 14 by laser-penetrating welding phase from the outside of the housing 2 inward.

[0285] As another specific example, we will only introduce the differences from the previous example. The difference is that the pole assembly 3 includes a pole 31 and an adapter plate 32. The pole 31 is installed on the end cap 21, and the adapter plate 32 is located between the pole 31 and the tab assembly 14. The pole 31, the adapter plate 32 and the tab assembly 14 are integrally welded by laser penetration welding from the outside of the housing 2 inward.

[0286] As another concrete example, such as Figures 18 to 21 As shown, this example is a further introduction based on any of the previous examples.

[0287] After the first two layers of separator 13 are wound up, the negative electrode 12 and the positive electrode 11 are wound up in sequence and separated by the separator 13. Since the tab 141 is located at the corner, the length of the tab 141 (along the winding direction C) will increase with the number of turns of the negative electrode 12, the positive electrode 11, and the separator 13. Because the thickness is very small when starting to wind, the tab at the corner will be very short, which is prone to burr problems. Therefore, the tab 141 can be pre-cut from the third or fourth turn.

[0288] The thickness of electrode assembly 1 (dimension along the third direction Z) = (twice the thickness of the separator 13 + the thickness of the negative electrode 12 + the thickness of the positive electrode 11) * the number of winding layers. The two layers of separator 13, the single layer of negative electrode 12 and the single layer of positive electrode 11 are regarded as a whole layer, and the value F is assigned as F = the thickness of separator 13 * 2 + the thickness of negative electrode 12 + the thickness of positive electrode 11.

[0289] At the first bend, the semicircular diameter of the positive electrode 11 is D1 = 2F, and the arc length is πD1 / 2 = 2πF / 2 = πF. Continuing to the second bend, it is wound into a single layer. At this point, the semicircular diameter of the positive electrode 11 at the second bend is D2 = 2F + F = 3F, and the length of the positive electrode 11 at the second bend is 3πF / 2. Similarly, the length of the positive electrode 11 at the third bend is 2πF, resulting in an arithmetic sequence with πF as the first term and a common difference of πF / 2. Therefore, let the nth term be Kn. =πF+(n-1)πF / 2=πF(n+1) / 2, so the length of the positive electrode 11 at each corner of the electrode assembly 1 is equal to Kn. When the top of the tab 141 (positive electrode tab) of the positive electrode 11 (the end away from the main body 16) is equal to the length of the positive electrode 11 at the corner 162, the top length t1 of the tab 141 of the positive electrode 11 is πF(n+1) / 2, where n refers to the number of corners counted from the winding center outwards. When the two ends of the tab 141 are not inclined along the winding direction C, the bottom length of the tab 141 is equal to the top length, then the bottom length p1 of the tab 141 of the positive electrode 11 is πF(n+1) / 2. When the tilt angle θ of the two ends of the tab 141 along the winding direction C is 30°, the bottom length p1 of the tab 141 of the positive electrode 11 is πF(n+1) / 2+(2√3 / 3)h1, where h1 is the height of the tab 141 of the positive electrode 11 (the dimension along the first direction X).

[0290] At the first corner, the semicircular diameter d1 of the negative electrode 12 is 2 * (thickness of the separator 13 + thickness of the negative electrode 12), and the value M is assigned as 2 * (thickness of the separator 13 + thickness of the negative electrode 12). At the second corner, the semicircular diameter d2 of the negative electrode 12 is M + F. At the third corner, the semicircular diameter of the negative electrode 12 is M + 2F. ... At the nth corner, the semicircular diameter of the negative electrode 12 is M + (n-1)F. Therefore, the length of the negative electrode 12 at each corner of the electrode assembly 1 is equal to [M + (n-1)F]π / 2, where n refers to the number of corners counted from the winding center outwards. When the top end (the end furthest from the main body 16) of the tab 141 (negative electrode tab) of the negative electrode 12 is equal to the length of the negative electrode 12 at the corner 162, the top end length t2 of the tab 141 of the negative electrode 12 is t2 = [M + (n-1)F]π / 2, where n refers to the number of corners counted outward from the winding center. When the two ends of the tab 141 are not inclined along the winding direction C, the bottom end length of the tab 141 is equal to the top end length, then the bottom end length p2 of the tab 141 of the negative electrode 12 is p2 = [M + (n-1)F]π / 2. When the tilt angle θ of the two ends of the tab 141 along the winding direction C is 30°, the bottom length p2 of the tab 141 of the negative electrode 12 is p2 = [M + (n-1)F]π / 2 + (2√3 / 3)h2, where h2 is the height of the tab 141 of the negative electrode 12 (the dimension along the first direction X).

[0291] It should be noted that the negative electrode 12 can extend the tab 141 from the odd-numbered bend, and the positive electrode 11 can extend the tab 141 from the even-numbered bend; or the positive electrode 11 can extend the tab 141 from the odd-numbered bend, and the negative electrode 12 can extend the tab 141 from the even-numbered bend.

[0292] The above embodiments are merely illustrative of the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and all should be covered within the scope of the specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way.

Claims

1. A battery cell, characterized in that, include: The housing includes a shell having an opening on one side along a first direction and an end cap that closes the opening, the end cap and the shell forming a receiving cavity; At least one pole assembly is disposed on the end cap; as well as At least one electrode assembly is disposed within the receiving cavity. The electrode assembly includes a main body and at least one tab assembly. The tab assembly includes a plurality of tabs that extend from the side of the main body facing the end cap and are stacked sequentially. At least a portion of the plurality of tabs is welded to the electrode post assembly. The same tab has an overlapping portion in the first direction. In the same tab assembly, the number of times all the tabs intersect with any straight line passing through the welding part along the first direction does not exceed the total number of all the tabs.

2. The battery cell according to claim 1, characterized in that, The electrode assembly has a wound structure. The main body of the electrode assembly includes a straight portion and two corner portions respectively disposed at both ends of the straight portion along a second direction. The stacking direction of the straight portion is consistent with a third direction. The first direction, the second direction and the third direction are perpendicular to each other. At least a portion of all the tabs in the same tab assembly extend from the same corner portion.

3. The battery cell according to claim 2, characterized in that, The electrode assembly is formed by winding a laminate including a positive electrode and a negative electrode, with a spacer sandwiched between the positive electrode and the negative electrode. The at least one tab assembly includes a positive tab assembly. The portion of the positive electrode sheet extending beyond the insulating member at the end near the end cap includes a plurality of tabs arranged sequentially at intervals along the winding direction; the plurality of tabs of the positive electrode sheet are stacked sequentially to form the positive electrode tab assembly; and / or The at least one tab assembly includes a negative tab assembly. The portion of the negative electrode sheet extending beyond the insulating member at the end near the end cap includes a plurality of tabs arranged sequentially at intervals along the winding direction, and the plurality of tabs of the negative electrode sheet are stacked sequentially to form the negative electrode tab assembly.

4. The battery cell according to claim 2 or 3, characterized in that, The electrode assembly has two or more parts and is arranged sequentially along the third direction.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The end face of the pole assembly facing away from the receiving cavity has a solder mark.

6. The battery cell according to any one of claims 1 to 5, characterized in that, The electrode assembly includes an electrode post, which is directly welded to the electrode tab.

7. The battery cell according to claim 6, characterized in that, The battery cell also includes an insulating member supported between the main body and the end cap. The insulating member has a through hole, through which all the tabs of the same tab assembly pass and at least some of the tabs are welded to the terminal post.

8. The battery cell according to any one of claims 1 to 5, characterized in that, The electrode assembly includes an electrode and an adapter plate. The electrode is disposed on the end cap, and the adapter plate is disposed in the receiving cavity. The end of the electrode facing the receiving cavity is welded to the adapter plate, and the adapter plate is welded to the electrode tab.

9. The battery cell according to claim 8, characterized in that, The surface of the adapter piece facing away from the end cap is a first plane, and the adapter piece is welded to the electrode tab through the first plane.

10. The battery cell according to claim 8 or 9, characterized in that, The surface of the adapter piece facing the end cap is a second plane, and the adapter piece is welded to the pole post through the second plane.

11. The battery cell according to any one of claims 8 to 10, characterized in that, The maximum thickness of the adapter piece is in the range of 0.8mm to 1.5mm.

12. The battery cell according to any one of claims 8 to 11, characterized in that, The pole, the adapter plate, and the electrode tab are integrally welded together.

13. The battery cell according to any one of claims 6 to 12, characterized in that, The end face of the pole facing away from the receiving cavity has a solder mark.

14. The battery cell according to any one of claims 1 to 13, characterized in that, The electrode assembly further includes at least one boss adjacent to the tab assembly. The boss includes a plurality of sheets that extend from the side of the main body facing the end cap and are stacked sequentially. Along the first direction, the size of the sheets is smaller than the size of the tab.

15. The battery cell according to claim 2, characterized in that, The at least one electrode assembly includes a positive electrode assembly and a negative electrode assembly, wherein the electrode of the positive electrode assembly is a positive electrode, and the electrode of the negative electrode assembly is a negative electrode. The positive electrode tab assembly is connected to one of the corner portions, and the negative electrode tab assembly is connected to the other corner portion.

16. The battery cell according to claim 15, characterized in that, The at least one electrode assembly includes a first electrode assembly and a second electrode assembly, wherein the first electrode assembly is welded to the positive electrode tab assembly, and the second electrode assembly is welded to the negative electrode tab assembly.

17. The battery cell according to claim 15 or 16, characterized in that, The surface of the positive electrode tab assembly facing the negative electrode tab assembly is parallel to the first direction; and / or, the surface of the negative electrode tab assembly facing the positive electrode tab assembly is parallel to the first direction.

18. The battery cell according to claim 15 or 16, characterized in that, The surface of the positive electrode tab assembly facing the negative electrode tab assembly extends obliquely from one end connected to the main body to the end away from the main body towards the side away from the negative electrode tab assembly. and / or The surface of the negative electrode tab assembly facing the positive electrode tab assembly extends obliquely from one end connected to the main body to the end away from the main body towards the side away from the positive electrode tab assembly.

19. The battery cell according to any one of claims 15 to 18, characterized in that, An arc-shaped surface is formed at the connection between the surface of the positive electrode assembly facing the negative electrode assembly and the end face of the main body; and / or An arc-shaped surface is formed at the connection between the surface of the negative electrode assembly facing the positive electrode assembly and the end face of the main body.

20. The battery cell according to any one of claims 1 to 19, characterized in that, The electrode assembly has a wound structure. The main body of the electrode assembly includes a straight portion and two corner portions respectively located at both ends of the straight portion along a second direction. The stacking direction of the straight portion is consistent with a third direction, and the first direction, the second direction, and the third direction are mutually perpendicular. The ratio of the dimension of the tab along the first direction to the dimension of the electrode assembly along the third direction is between 0.125 and 0.

15.

21. The battery cell according to any one of claims 1 to 20, characterized in that, Along the first direction, the size of the electrode tab is in the range of 0.5mm to 1.5mm.

22. A battery device, characterized in that, It includes multiple battery cells as described in any one of claims 1 to 21.

23. An energy storage device, characterized in that, The energy storage device includes a plurality of battery cells as described in any one of claims 1 to 21 or a plurality of battery devices as described in claim 22, wherein the battery cells or the battery devices are used to store or provide electrical energy.

24. An electrical appliance, characterized in that, The electrical device includes a plurality of battery cells as described in any one of claims 1 to 21 or a plurality of battery devices as described in claim 22, wherein the battery cells or the battery devices are used to store or provide electrical energy.

Images