Battery monomer, battery device and electric equipment
By dividing the battery tabs into a multi-layered structure, gaps are formed to hide particulate matter, solving the problem of particulate matter wearing off the tabs when the battery vibrates, thus improving the reliability of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
- Filing Date
- 2024-10-09
- Publication Date
- 2026-04-10
AI Technical Summary
During battery vibration, particulate matter can easily accumulate at the end cap and wear down the tabs, causing the connection between the tabs and electrode leads to fail and affecting the reliability of the battery.
The first electrode tab is divided into a first electrode tab layer group and a second electrode tab layer group. A portion of the second electrode tab layer group extends beyond the first electrode tab layer group and is welded to the first electrode lead-out component to form a gap to hide particulate matter, reduce the contact between particulate matter and the first electrode tab, and reduce the risk of wear.
By transferring the risk of wear to the second tab layer, the possibility of failure in the connection between the first tab and the electrode lead is reduced, thus improving the reliability of the battery cell.
Smart Images
Figure CN121840133A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of battery technology, and in particular relates to a battery cell, a battery device, and an electrical device. Background Technology
[0002] With the development of new energy technologies, batteries are being used more and more widely. For example, batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in military equipment and aerospace and many other fields.
[0003] The development of battery technology must take into account multiple design factors, such as energy density, cycle life, assembly efficiency, and processing technology, as well as battery reliability. Summary of the Invention
[0004] This application provides a battery cell, a battery device, and an electrical appliance that can improve reliability.
[0005] According to a first aspect of this application, a battery cell is provided, comprising a casing, a first electrode lead, and an electrode assembly. The electrode assembly includes a main body and a first tab. The first tab includes a first tab layer group and a second tab layer group. The first tab layer group includes a plurality of stacked first tab layers, and the second tab layer group includes a plurality of stacked second tab layers. Both the first and second tab layers extend from the end of the main body facing the first electrode lead. At least a portion of the first tab layer group is located between the second tab layer group and the first electrode lead, and is welded to the second tab layer group and the first electrode lead. The first tab layer has a first free end away from the main body, and along the extending direction of the first tab layer, at least a portion of the second tab layer extends beyond the first free end of each first tab layer.
[0006] A gap is formed between the portion of the second tab layer extending beyond the first tab layer and the casing wall where the first electrode lead is located. When the battery cell is inverted (with the casing wall where the first electrode lead is located at the bottom), particles inside the battery cell easily accumulate and hide in this gap, reducing the possibility of particles contacting other parts of the first tab. When the battery cell vibrates, particles rub against the portion of the second tab layer extending beyond the first tab layer, and this portion is not used to connect the first electrode lead. In other words, the embodiments of this application can transfer the portion of the first tab that is easily worn by particles to the portion of the second tab layer extending beyond the first tab layer, reducing the possibility of wear on the portion of the first tab used to connect the first electrode lead, which helps to reduce the risk of connection failure between the first tab and the first electrode lead, and improves the reliability of the battery cell.
[0007] In some embodiments, along the extending direction of the first tab layer, the second tab layer adjacent to the first tab layer group extends beyond the first free end of each first tab layer. Thus, at least a portion of the gap can be formed between the second tab layer closest to the first electrode lead and the first electrode lead. Along the arrangement direction of the first electrode lead and the electrode assembly, the gap is relatively small, which helps to retain particles entering the gap within the gap, reducing the risk of particles contacting or abrading other parts of the first tab.
[0008] In some embodiments, the second tab layer has a second free end away from the main body. In two adjacent second tab layers, the second tab layer closer to the first tab layer group extends beyond the second free end of the other second tab layer along the extension direction of the first tab layer. The gap is completely formed between the second tab layer closest to the first tab layer group and the first electrode lead-out member. On the one hand, the remaining second tab layers do not obstruct the entry of particles into the gap, reducing the difficulty for particles to enter the gap; on the other hand, it can also increase the size of the gap along the extension direction of the first tab layer, reducing the possibility of particles moving out of the gap, which is beneficial to the risk of further particles contacting or abrading other parts of the first tab.
[0009] In some embodiments, the first free ends of the plurality of first tab layers are flush along the extending direction of the first tab layer. This increases the space of the gap, reduces the obstruction effect of the first tab layer on particulate matter entering the gap, helps reduce the difficulty of particulate matter entering the gap, increases the likelihood that particulate matter only wears down the portion of the second tab layer extending beyond the first tab layer, and reduces the risk of particulate matter contacting or wearing down other parts of the first tab.
[0010] In some embodiments, the direction of the second tab layer extending beyond the first tab layer is parallel to the thickness direction of the battery cell, and the second tab layer is separated from the bisecting plane of the battery cell along the thickness direction. This reduces the possibility of interference between the first tabs of multiple electrode assemblies, facilitating the assembly of the battery cells.
[0011] In some embodiments, along the thickness direction of the battery cell, the distance d from the first free end of the second tab layer closest to the bisecting plane to the first tab layer closest to the bisecting plane is 5mm ≥ d ≥ 3mm. This allows for a larger gap in the thickness direction, facilitating the concealment of particles and reducing the risk of particle abrasion on the portion of the first tab used for connection with the first electrode lead. It also reduces the risk of the second tab layer interfering with other structures or short-circuiting due to inverted insertion into the main body.
[0012] In some embodiments, along the extending direction of the first tab layer, each second tab layer extends beyond the first free end of all first tab layers. Thus, each second tab layer has a portion extending beyond the first tab layer, increasing the overall thickness of the portion of the second tab layer group extending beyond the first tab layer group. This makes the portion of the second tab layer group extending beyond the first tab layer group less susceptible to wear and damage from particles hidden within the gaps, further reducing the likelihood of particles contacting the portion of the first tab used for connection with the first electrode lead, and lowering the risk of connection failure between the first tab and the first electrode lead.
[0013] In some embodiments, each second tab layer extends from the main body for the same length, and each first tab layer extends from the main body for the same length; the length of the second tab layer extending from the main body is greater than the length of the first tab layer extending from the main body. Multiple second tab layers and multiple first tab layers form a gradient tab with only two different lengths, facilitating die-cutting. Furthermore, the second tab layers can be formed by edgeless die-cutting, and the first tab layers can be formed by edge die-cutting, which can significantly reduce the width of the substrate before die-cutting, thus saving substrate usage, reducing the risk of tape breakage during cold pressing, and minimizing waste of substrate and active material.
[0014] In some embodiments, the length of the first tab layer extending from the main body is L1, and the length of the second tab layer extending from the main body is L2, where 10mm ≥ L2 - L1 ≥ 3mm. On one hand, this facilitates die-cutting of the first tab layer and eliminates the need for die-cutting allowance for the second tab layer, thus saving substrate usage. On the other hand, it reduces the width of the substrate, lowering the risk of tape breakage during cold pressing. Furthermore, it reduces the size of the second tab layer extending beyond the first free end, reducing the risk of interference between the second tab layer and other structures or short circuits caused by its inverted insertion into the main body.
[0015] In some embodiments, the first tab layer group, the second tab layer group, and the first electrode lead are welded to form a first welded portion, and the first free ends of each first tab layer are spaced apart from the first welded portion. Each first tab layer has a certain allowance on one side of the first welded portion along the extension direction of the first tab layer, which can reduce the possibility of particles hidden in the gaps contacting the first welded portion, reduce the risk of the first welded portion being worn by particles, and further reduce the risk of connection failure between the first tab and the first electrode lead.
[0016] In some embodiments, a portion of each first tab layer surrounds the first weld portion. This not only improves the strength of the first weld portion but also extends the distance that particles migrate to the first weld portion from various directions along the edge of the first tab layer, increasing the difficulty of particle migration to the first weld portion and helping to reduce the risk of particle wear on the first weld portion leading to connection failure between the first tab and the first electrode lead.
[0017] In some embodiments, each first tab layer of the first tab layer group is welded to form a second welded portion, and each second tab layer of the second tab layer group is welded to form a third welded portion. Both the second and third welded portions are connected to the first welded portion. The second welded portion can improve the connection strength of the multiple first tab layers, making the first tab layer group form a whole; the third welded portion can improve the connection strength of the multiple second tab layers, making the second tab layer group form a whole. This helps to reduce the welding difficulty between the first tab layer group, the second tab layer group, and the first electrode lead, and can reduce the risk that some first tab layers and / or some second tab layers are not connected to the first electrode lead, which helps to improve the current carrying capacity and reduce heat generation.
[0018] In some embodiments, at least a portion of the second weld portion surrounds the first weld portion and is directly connected to the first weld portion; and / or, at least a portion of the third weld portion surrounds the first weld portion and is directly connected to the first weld portion. This helps to reduce the risk of incomplete soldering of the first weld portion and also reduces the risk of cracking between the outer periphery of the first weld portion and the first tab layer, further improving the current carrying capacity.
[0019] According to a second aspect of this application, this application also provides a battery device comprising a plurality of battery cells provided according to any embodiment of the first aspect of this application.
[0020] According to a third aspect of this application, embodiments of this application also provide an electrical device, which includes a battery device provided in any embodiment of the second aspect of this application, the battery device being used to provide electrical energy. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 These are schematic diagrams of the vehicle structure provided in some embodiments of this application.
[0023] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application.
[0024] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application.
[0025] Figure 4 for Figure 3The diagram shows the structure of the electrode assembly and end cap of the battery cell.
[0026] Figure 5 for Figure 3 The diagram shows a partial structural schematic of the end cap, first adapter, and first tab of the battery cell.
[0027] Figure 6 for Figure 5 A sectional view taken along direction AA.
[0028] Figure 7 for Figure 3 The diagram shows the structure of the first electrode of the battery cell after it has been unfolded.
[0029] In the attached image:
[0030] Vehicle 1, battery pack 2, controller 3, motor 4, housing 5, battery cell 6;
[0031] Electrode assembly 10, main body 11, first tab 12, first tab layer 121, first free end 1211, second tab layer 122, second free end 1221, first tab layer group 12a, second tab layer group 12b, second tab 13, outer shell 20, housing 21, end cap 22, first electrode lead-out member 30, first electrode terminal 31, first adapter piece 32, second electrode lead-out member 40, second electrode terminal 41, second adapter piece 42, first welding part 51, second welding part 52, third welding part 53, first housing part 5a, second housing part 5b, accommodating space 5c, bisecting plane a, gap M, thickness direction X. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0033] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.
[0034] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.
[0035] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0036] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0037] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.
[0038] In this application, "multiple" means two or more (including two).
[0039] In the embodiments of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.
[0040] In this embodiment of the application, the battery cell can be a secondary battery cell, which refers to a battery cell that can be used again after being discharged by recharging to activate the active materials.
[0041] A battery cell typically includes a casing and an electrode assembly disposed within the casing. The electrode assembly includes a positive electrode and a negative electrode. 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. For example, the electrode assembly also includes a separator disposed between the positive and negative electrodes. The separator serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.
[0042] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., but the embodiments of this application are not limited to this.
[0043] As an example, the battery cell can be a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.
[0044] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.
[0045] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.
[0046] A battery device typically includes a housing for encapsulating one or more individual battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the individual battery cells.
[0047] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into an independent module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties. The battery cell assembly can be housed within a housing by fixing the battery module within the housing. As an example, the housing can include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, creating a closed space inside the housing to house the battery cell assembly.
[0048] 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.
[0049] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.
[0050] A typical battery cell includes an electrode assembly, a housing, and electrode leads. The electrode assembly is housed within the housing, and the electrode leads are located on end caps of the housing. The electrode assembly includes tabs that connect to the electrode leads. The electrode leads are used to electrically connect the electrode assembly to an external circuitry of the battery cell to enable charging or discharging of the battery cell.
[0051] During battery manufacturing, large particles may be generated inside the battery. When a battery is used upside down, with the end cap at the bottom, these particles can accumulate on the end cap. As the battery vibrates, these particles may rub against the tabs, causing wear and tear. This can lead to connection failure between the tabs and electrode leads, affecting the reliability of the individual battery cells.
[0052] In view of this, the present application provides a technical solution that divides the first tab into a first tab layer group and a second tab layer group. At least a portion of the first tab layer group is disposed between and welded to the first electrode lead and the second tab layer group. At least a portion of the second tab layer in the second tab layer group extends beyond each of the first tab layers in the first tab layer group. The portion of the second tab layer extending beyond the first tab layer is most likely to come into contact with particulate matter and be worn by it, reducing the possibility of wear on the connection between the first tab layer group and the first electrode lead, which helps to reduce the risk of connection failure between the first tab and the first electrode lead and improves the reliability of the battery cell.
[0053] The technical solutions improved in the embodiments of this application can be used in battery devices and electrical equipment that uses battery devices as power sources or various energy storage systems that use battery devices as energy storage elements.
[0054] Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.
[0055] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.
[0056] Figure 1 This is a schematic diagram of the vehicle structure provided for some embodiments of this application. (Refer to...) Figure 1 The vehicle 1 includes a battery device 2, which may be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.
[0057] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.
[0058] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.
[0059] Figure 2 This is an exploded structural diagram of a battery device provided in some embodiments of this application. (Refer to...) Figure 2 The battery device 2 includes a housing 5 and battery cells 6, with the battery cells 6 housed within the housing 5.
[0060] The housing 5 is used to house the battery cell 6, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the battery cell 6. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.
[0061] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.
[0062] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.
[0063] In the battery device 2, there can be one or more battery cells 6. If there are multiple battery cells 6, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 6 are connected in both series and parallel. Multiple battery cells 6 can be directly connected in series, in parallel, or in a mixed configuration, and then the whole assembly of multiple battery cells 6 is housed in the housing 5. Alternatively, multiple battery cells 6 can first be connected in series, in parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in a mixed configuration to form a whole assembly, which is then housed in the housing 5.
[0064] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. (Refer to...) Figure 3 This application provides a battery cell 6, which includes a housing 20 and an electrode assembly 10, with the electrode assembly 10 housed within the housing 20.
[0065] There can be one electrode assembly 10 or multiple electrode assemblies.
[0066] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 6, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.
[0067] The outer casing 20 is used to encapsulate the electrode assembly 10 and electrolyte components. The outer casing 20 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.
[0068] In some embodiments, the positive electrode includes a positive electrode sheet. The positive electrode sheet may include a positive electrode current collector and a layer of positive electrode active material disposed on at least one surface of the positive electrode current collector.
[0069] 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.
[0070] In some embodiments, the negative electrode includes a negative electrode sheet. The negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one surface of the negative electrode current collector.
[0071] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.
[0072] In some embodiments, the electrode assembly 10 further includes a separator for separating the positive and negative electrode plates. The separator can reduce the risk of short circuits between the positive and negative electrodes while allowing active ions to pass through.
[0073] In some embodiments, the separator includes a separator membrane. The separator membrane in this application can be any known porous structure separator membrane with good chemical and mechanical stability.
[0074] In some embodiments, the electrode assembly 10 is a wound structure. Exemplarily, both the positive and negative electrode sheets are strip structures, and the positive electrode sheet, the separator, and the negative electrode sheet are wound into a wound structure.
[0075] In some embodiments, the electrode assembly 10 has a stacked structure.
[0076] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.
[0077] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.
[0078] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.
[0079] In some embodiments, the electrode assembly 10 may be cylindrical, flat, or polygonal, etc.
[0080] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.
[0081] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the battery cell 6. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte, and other components.
[0082] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 6.
[0083] The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The housing 21 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, aluminum-plastic film, steel-plastic film, etc.
[0084] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the battery cell 6 can have higher structural strength and improve reliability.
[0085] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.
[0086] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.
[0087] In some embodiments, the electrode assembly 10 includes a main body 11, a first tab 12, and a second tab 13. One of the first tab 12 and the second tab 13 is a positive tab, and the other is a negative tab. The main body 11 may include a portion of the positive electrode plate coated with an active material layer, a portion of the negative electrode plate coated with an active material layer, and a separator. The active material in the active material layer is used to undergo an electrochemical reaction with an electrolyte or the like to generate a charge-discharge process.
[0088] In some embodiments, the battery cell 6 includes a first electrode lead 30 and a second electrode lead 40 disposed on the housing 20. The first electrode lead 30 is electrically connected to a first tab 12 of the electrode assembly 10, and the second electrode lead 40 is electrically connected to a second tab 13 of the electrode assembly 10. The first electrode lead 30 and the second electrode lead 40 can be used to electrically connect the electrode assembly 10 to a circuit outside the battery cell 6 to enable charging and discharging of the electrode assembly 10. Exemplarily, at least a portion of the first electrode lead 30 and the second electrode lead 40 is exposed to the outside of the battery cell 6 to facilitate connection with other components (e.g., a busbar) to extract the electrical energy generated by the electrode assembly 10.
[0089] For example, the first electrode lead-out member 30 and the second electrode lead-out member 40 can be disposed on the end cap 22 or on the housing 21.
[0090] In some embodiments, the first tab 12 extends from the end of the main body 11 facing the first electrode lead-out member 30. The second tab 13 extends from the end of the main body 11 facing the second electrode lead-out member 40.
[0091] In some examples, the first electrode lead-out 30 and the second electrode lead-out 40 may be located on the same side of the main body 11, or they may be located on opposite sides of the main body 11.
[0092] Optionally, the first electrode lead-out member 30 may include a first electrode terminal 31 and a first adapter piece 32, with the first electrode terminal 31 disposed on the housing 20 and the first adapter piece 32 connected to the first electrode terminal 31. The second electrode lead-out member 40 may include a second electrode terminal 41 and a second adapter piece 42, with the second electrode terminal 41 disposed on the housing 20 and the second adapter piece 42 connected to the second electrode terminal 41.
[0093] Figure 4 for Figure 3The diagram shows the structure of the electrode assembly and end cap of the battery cell. Figure 5 for Figure 3 The diagram shows a partial structural representation of the end cap, first adapter, and first tab of the battery cell. Figure 6 for Figure 5 A sectional view taken along direction AA. Figure 7 for Figure 3 The diagram shows the structure of the first electrode of the battery cell after it has been unfolded.
[0094] Reference Figures 3 to 7 In some embodiments, the battery cell 6 includes an electrode assembly 10, a housing 20, and a first electrode lead 30. The first electrode lead 30 is disposed within the housing 20. The electrode assembly 10 is housed within the housing 20. The electrode assembly 10 includes a main body 11 and a first tab 12. The first tab 12 includes a first tab layer group 12a and a second tab layer group 12b. The first tab layer group 12a includes a plurality of stacked first tab layers 121, and the second tab layer group 12b includes a plurality of stacked second tab layers 122. Both the first tab layers 121 and the second tab layers 122 extend from the end of the main body 11 facing the first electrode lead 30. At least a portion of the first tab layer group 12a is located between the second tab layer group 12b and the first electrode lead 30, and is welded to the second tab layer group 12b and the first electrode lead 30. The first tab layer 121 has a first free end 1211 away from the main body 11, and at least a portion of the second tab layer 122 extends beyond the first free end 1211 of each of the first tab layers 121 along the extending direction of the first tab layer 121.
[0095] The first electrode 12 can be one or more.
[0096] In some examples, the first electrode lead-out 30 may include a first electrode terminal 31 and a first adapter plate 32. The first tab layer group 12a and the second tab layer group 12b are soldered to the first adapter plate 32.
[0097] In other examples, the first electrode lead-out 30 may also include only the first electrode terminal, with the first tab layer group 12a and the second tab layer group 12b soldered to the first electrode terminal.
[0098] The first tab layer group 12a and the second tab layer group 12b are stacked together for welding to the first electrode lead-out member 30.
[0099] At least a portion of the first tab layer group 12a may be attached to the first electrode lead 30. For example, the first tab layer 121 in the first tab layer group 12a that is closest to the first electrode lead 30 is attached to the first electrode lead 30. The first tab layer 121 in the first tab layer group 12a that is furthest from the first electrode lead 30 is attached to the second tab layer group 12b.
[0100] After being led out from the main body 11, the first electrode layer 121 and the second electrode layer 122 can be bent and extended between the main body 11 and the shell wall (e.g., end cap 22) where the first electrode lead-out member 30 is located.
[0101] Optionally, the electrode assembly 10 can be a wound structure, and multiple tab layers can be bent from the inner side near the winding center to the outer side away from the winding center, with the degree of bending of the tab layer being greater the closer it is to the winding center.
[0102] The first tab layers 121 of the first tab layer group 12a are further away from the winding center of the electrode assembly 10 than the second tab layers 122 of the second tab layer group 12b. The bending degree of the second tab layers 122 of the second tab layer group 12b is greater than that of the first tab layers 121 of the first tab layer group 12a. Therefore, at least a portion of the second tab layers 122 extend from the main body portion 11 in greater length than the first tab layers 121 extend from the main body portion 11.
[0103] The welded joint formed by welding the first tab layer group 12a, the second tab layer group 12b and the first electrode lead-out member 30 can conduct current. The current of each first tab layer 121 and the current of each second tab layer 122 are conducted to the first electrode lead-out member 30 through the welded joint.
[0104] Because the first tab layer group 12a is closer to the first electrode lead 30 than the second tab layer group 12b, and at least a portion of the second tab layer 122 extends beyond each of the first tab layers 121, a gap M is formed between the portion of the second tab layer 122 extending beyond the first tab layer 121 and the casing wall where the first electrode lead 30 is located. When the battery cell 6 is inverted (with the casing wall where the first electrode lead 30 is located at the bottom), particles inside the battery cell 6 easily accumulate and hide in this gap M, reducing the possibility of particles contacting other parts of the first tab 12. When the battery cell 6 vibrates, particles rub against the portion of the second tab layer 122 extending beyond the first tab layer 121, and the portion of the second tab layer 122 extending beyond the first tab layer 121 is not used to connect to the first electrode lead 30. In other words, the embodiment of this application can transfer the part of the first tab 12 that is easily worn by particulate matter to the part of the second tab layer 122 that extends beyond the first tab layer 121, thereby reducing the possibility of wear on the part of the first tab 12 used to connect the first electrode lead 30. This helps to reduce the risk of connection failure between the first tab 12 and the first electrode lead 30 and improve the reliability of the battery cell 6.
[0105] In some embodiments, along the extending direction of the first tab layer 121, the second tab layer 122 adjacent to the first tab layer group 12a extends beyond the first free end 1211 of each first tab layer 121.
[0106] The second tab layer 122, which is adjacent to the first tab layer group 12a, is closest to the first tab layer group 12a. Optionally, the second tab layer 122, which is adjacent to the first tab layer group 12a, may be attached to the first tab layer group 12a.
[0107] The second tab layer 122, which is spaced apart from the first tab layer group 12a, may extend beyond at least part of the first free end 1211 of the first tab layer 121, or it may not extend beyond the first free end 1211 of any of the first tab layers 121.
[0108] The second tab layer 122 adjacent to the first tab layer group 12a extends beyond the first free end 1211 of each first tab layer 121. At least a portion of the gap M can be formed between the second tab layer 122 closest to the first electrode lead 30 and the first electrode lead 30. Along the arrangement direction of the first electrode lead 30 and the electrode assembly 10, the size of the gap M is relatively small, which is beneficial to keep the particles entering the gap M within the gap M and reduce the risk of particles contacting or abrading other parts of the first tab 12.
[0109] In some embodiments, the second tab layer 122 has a second free end 1221 away from the main body portion 11. In two adjacent second tab layers 122, the second tab layer 122 that is closer to the first tab layer group 12a extends beyond the second free end 1221 of the other second tab layer 122 along the extension direction of the second tab layer 122.
[0110] The spacing between the second free ends 1221 of each two adjacent second tab layers 122 can be the same or different.
[0111] The second tab layers 122 of the second tab layer group 12b are distributed in a stepped manner. The second tab layer 122 closest to the first tab layer group 12a has the largest size extending beyond the first free end 1211 of the first tab layer 121. The gap M is completely formed between the second tab layer 122 closest to the first tab layer group 12a and the first electrode lead-out member 30. On the one hand, the other second tab layers 122 will not hinder the particles entering the gap M, reducing the difficulty for particles to enter the gap M; on the other hand, it can also increase the size of the gap M along the extension direction of the first tab layer 121, reducing the possibility of particles moving out of the gap M, which is beneficial to the risk of further particles contacting or abrading other parts of the first tab 12.
[0112] In some embodiments, the first free ends 1211 of the plurality of first tab layers 121 are flush along the extending direction of the first tab layer 121.
[0113] Optionally, the lengths of the multiple first tab layers 121 extending from the main body 11 are different, which is beneficial for the first free ends 1211 of the first tab layers 121 to be flush after bending.
[0114] The first free ends 1211 of each first tab layer 121 are flush. The edge of the gap M near the first tab layer 121 is relatively flush, which can increase the space of the gap M, reduce the obstruction effect of the first tab layer 121 on the entry of particles into the gap M, reduce the difficulty of particles entering the gap M, increase the possibility that particles only wear the part of the second tab layer 122 that extends beyond the first tab layer 121, and reduce the risk of particles contacting or wearing other parts of the first tab 12.
[0115] In some embodiments, the direction of the second tab layer 122 extending beyond the first tab layer 121 is parallel to the thickness direction X of the battery cell 6, and the second tab layer 122 is separated from the bisecting plane a of the battery cell 6 along the thickness direction X.
[0116] Bisector a bisects the cell 6 along the thickness direction X, and the thickness direction X is perpendicular to bisector a.
[0117] The second free end 1221 of the second tab layer 122 is spaced apart from the bisecting plane a, and the second tab layer 122 does not intersect the bisecting plane a.
[0118] When there are multiple electrode assemblies 10, the multiple electrode assemblies 10 are arranged along the thickness direction X. The first electrode tabs 12 of the multiple electrode assemblies 10 are arranged opposite each other along the thickness direction X and are simultaneously connected to the first electrode lead-out member 30.
[0119] The second tab layer 122 is separated from the bisecting plane a, which can reduce the possibility of interference between the first tabs 12 of multiple electrode assemblies 10 and facilitate the assembly of the battery cell 6.
[0120] In some embodiments, along the thickness direction X, the distance d from the second tab layer 122 closest to the bisecting plane a to the first free end 1211 of the first tab layer 121 closest to the bisecting plane a is 5mm ≥ d ≥ 3mm.
[0121] Optionally, d can be 3mm, 3.5mm, 4mm, 4.5mm, 5mm, or any value between two of them.
[0122] In this embodiment, setting d to be greater than or equal to 3 mm allows the gap M to have a larger size in the thickness direction X, which facilitates the concealment of particles and reduces the risk of particles wearing down the part of the first tab 12 used to connect with the first electrode lead 30. Setting d to be less than or equal to 5 mm reduces the length of the part of the second tab layer 122 that is not connected and constrained, reducing the risk of the second tab layer 122 interfering with other structures or being inserted into the main body 11 and causing a short circuit.
[0123] In some embodiments, each second tab layer 122 extends beyond the first free end 1211 of all first tab layers 121.
[0124] Along the thickness direction X, the second tab layer 122, which is furthest from the bisecting plane a, extends beyond the first free end 1211 of the first tab layer 121, which is closest to the bisecting plane a.
[0125] The second tab layer 122 that is furthest from the bisecting plane a is the shortest second tab layer 122 in the thickness direction X of the second tab layer group 12b. In other words, in the second tab layer group 12b, the second tab layer 122 that is furthest from the bisecting plane a has the shortest extension in the thickness direction X.
[0126] The first tab layer 121 closest to the bisecting plane a is the longest first tab layer 121 extending along the thickness direction X in the first tab layer group 12a. In other words, in the first tab layer group 12a, the first tab layer 121 closest to the bisecting plane a extends the longest along the thickness direction X.
[0127] Each second tab layer 122 extends beyond the first free end 1211 of all first tab layers 121. Therefore, each second tab layer 122 has a portion extending beyond the first tab layer 121, increasing the overall thickness of the portion of the second tab layer group 12b that extends beyond the first tab layer group 12a. This makes the portion of the second tab layer group 12b extending beyond the first tab layer group 12a less susceptible to wear and damage from particles hidden within the gap M. This further reduces the likelihood of particles contacting the portion of the first tab 12 used for connection with the first electrode lead 30, thus lowering the risk of connection failure between the first tab 12 and the first electrode lead 30.
[0128] In some embodiments, the second tab layers 122 extend from the main body 11 by the same length, and the first tab layers 121 extend from the main body 11 by the same length. The length of the second tab layers 122 extending from the main body 11 is greater than the length of the first tab layers 121 extending from the main body 11.
[0129] The length of the first tab layer 121 extending from the main body 11 can be measured by flattening the first tab layer 121. The length of the second tab layer 122 extending from the main body 11 can be measured by flattening the second tab layer 122.
[0130] Multiple second tab layers 122 and multiple first tab layers 121 form gradient tabs with only two different lengths, which facilitates die-cutting. Furthermore, the second tab layers 122 can be formed by edgeless die-cutting, and the first tab layers 121 can be formed by edge die-cutting, which can significantly reduce the width of the substrate before die-cutting, thus saving substrate usage, reducing the risk of tape breakage during substrate cold pressing, and reducing waste of substrate and active material.
[0131] In some embodiments, the length of the first tab layer 121 extending from the main body 11 is L1, and the length of the second tab layer 122 extending from the main body 11 is L2, where 10mm ≥ L2 - L1 ≥ 3mm.
[0132] Optionally, the difference between L2 and L1 can be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm or any value between two of them.
[0133] In this embodiment, the difference between L2 and L1 is set to be greater than or equal to 3mm, which facilitates the die-cutting of the first tab layer 121 and eliminates the need to reserve die-cutting allowance for the second tab layer 122, thus saving substrate usage. Setting the difference between L2 and L1 to be less than or equal to 10mm can reduce the width of the substrate, reduce the risk of tape breakage during the cold pressing process, and also reduce the size of the second tab layer 122 extending beyond the first free end 1211, thus reducing the risk of the second tab layer 122 interfering with other structures or short-circuiting when inserted into the main body 11.
[0134] In some embodiments, the first tab layer group 12a, the second tab layer group 12b and the first electrode lead-out member 30 are welded to form a first welding part 51, and the first free end 1211 of each first tab layer 121 is spaced apart from the first welding part 51.
[0135] In other words, the first free end 1211 of each first tab layer 121 is not directly connected to the first welding part 51, and a part of each first tab layer 121 is located between its own first free end 1211 and the first welding part 51.
[0136] In some examples, the first weld portion 51 can be formed by welding the first tab layer group 12a, the second tab layer group 12b and the first electrode lead-out member 30 together in one step.
[0137] In other examples, two of the first tab layer group 12a, the second tab layer group 12b and the first electrode lead-out member 30 may be welded together to form a solder mark, and then the solder mark may be welded to the remaining one to form a first welded part 51.
[0138] Optionally, the first tab layer 121 includes a first stacked segment and a first bent segment, the first bent segment being bent from one end of the first stacked segment and connected to the main body portion 11. The second tab layer 122 includes a second stacked segment and a second bent segment, the second bent segment being bent from one end of the second stacked segment and connected to the main body portion 11. The first stacked segments of the plurality of first tab layers 121 are located between the second stacked segments of the plurality of second tab layers and the first electrode lead-out member 30, and the first stacked segments of the plurality of first tab layers, the second stacked segments of the plurality of second tab layers, and the first electrode lead-out member 30 are welded to form a first welded portion 51.
[0139] Each first tab layer 121 has a certain amount of allowance on one side of the first welding part 51 along the extension direction of the first tab layer 121, which can reduce the possibility of particles hidden in the gap M contacting the first welding part 51, reduce the risk of the first welding part 51 being worn by particles, and help to further reduce the risk of connection failure between the first tab 12 and the first electrode lead 30.
[0140] In some embodiments, a portion of each first tab layer 121 surrounds the first weld portion 51.
[0141] The portion of each first tab layer 121 surrounding the first welding part 51 can be directly connected to the first welding part 51, or it can be indirectly connected to the first welding part 51 through other structures.
[0142] The first weld portion 51 is formed in the middle region of each first tab layer 121. This not only improves the firmness of the first weld portion 51, but also, since the first weld portion 51 is spaced apart from the edge of each first tab layer 121, it can extend the distance for particles to migrate to the first weld portion 51 from all directions of the edge of the first tab layer 121, increasing the difficulty for particles to migrate to the first weld portion 51. This helps to reduce the risk of the first tab 12 and the first electrode lead-out member 30 failing to connect due to wear of the first weld portion 51 by particles.
[0143] In some embodiments, the second free ends 1221 of each second tab layer 122 are spaced apart from the first weld portion 51. A portion of each second tab layer 122 surrounds the first weld portion 51 to further increase the difficulty of particulate matter migrating to the first weld portion 51.
[0144] In some embodiments, each of the first tab layers 121 of the first tab layer group 12a is welded to form a second welded portion 52, and each of the second tab layers 122 of the second tab layer group 12b is welded to form a third welded portion 53. Both the second welded portion 52 and the third welded portion 53 are connected to the first welded portion 51.
[0145] The second welding part 52 can be directly connected to the first welding part 51, or it can be indirectly connected to the first welding part 51 through a part of the first tab layer 121.
[0146] The third welding part 53 can be directly connected to the first welding part 51, or it can be indirectly connected to the first welding part 51 through a part of the second tab layer 122.
[0147] The second welding part 52 and the third welding part 53 are both connected to the first welding part 51. The current of the first electrode layer group 12a can be conducted to the first electrode lead-out member 30 through the second welding part 52 and the first welding part 51. The current of the second electrode layer group 12b can be conducted to the first electrode lead-out member 30 through the third welding part 53 and the first welding part 51.
[0148] During welding, each of the first tab layers 121 of the first tab layer group 12a can be welded to form a second weld mark, and each of the second tab layers 122 of the second tab layer group 12b can be welded to form a third weld mark; then a part of the second weld mark and a part of the third weld mark are welded to form a first welded part 51, the part of the second weld mark that is not welded again forms a second welded part 52, and the part of the third weld mark that is not welded again forms a third welded part 53.
[0149] The welding forming processes of the first welding part 51, the second welding part 52, and the third welding part 53 can be the same or different.
[0150] Optionally, each first tab layer 121 of the first tab layer group 12a can be ultrasonically welded to form a second weld mark, and each second tab layer 122 of the second tab layer group 12b can be ultrasonically welded to form a third weld mark. Correspondingly, both the second welded portion 52 and the third welded portion 53 can be formed by ultrasonic welding.
[0151] Optionally, a portion of the second weld mark and a portion of the third weld mark may be formed into the first weld portion 51 by ultrasonic welding or laser welding.
[0152] The second welding part 52 can improve the connection strength of the multiple first tab layers 121, so that the first tab layer group 12a forms a whole; the third welding part 53 can improve the connection strength of the multiple second tab layers 122, so that the second tab layer group 12b forms a whole. In this way, it is beneficial to reduce the welding difficulty between the first tab layer group 12a, the second tab layer group 12b and the first electrode lead-out member 30, and can reduce the risk that some first tab layers 121 and / or some second tab layers 122 are not connected to the first electrode lead-out member 30, which is beneficial to improve the current carrying capacity and reduce heat generation.
[0153] In some embodiments, at least a portion of the second weld portion 52 surrounds the first weld portion 51 and is directly connected to the first weld portion 51. In other words, the outer periphery of the first weld portion 51 is directly connected to the second weld portion 52.
[0154] The direct connection between the first weld portion 51 and the second weld portion 52 enhances the welding effect and increases the welding strength. Furthermore, in the second weld portion 52, the interlayer gaps between the multiple first tab layers 121 are compressed. The direct connection between the first weld portion 51 and the second weld portion 52 reduces the risk of incomplete welding in the first weld portion 51 and also reduces the risk of cracking between the outer periphery of the first weld portion 51 and the first tab layer 121, further improving the current carrying capacity.
[0155] In some embodiments, at least a portion of the third weld portion 53 surrounds the first weld portion 51 and is directly connected to the first weld portion 51. In other words, the outer periphery of the first weld portion 51 is directly connected to the third weld portion 53.
[0156] The direct connection between the first weld portion 51 and the third weld portion 53 enhances the welding effect and increases the welding strength. Furthermore, in the third weld portion 53, the interlayer gaps between the multiple second tab layers 122 are compressed. The direct connection between the first weld portion 51 and the third weld portion 53 reduces the risk of incomplete welding in the first weld portion 51 and also reduces the risk of cracking between the outer periphery of the first weld portion 51 and the second tab layer 122, further improving the current carrying capacity.
[0157] According to some embodiments of this application, this application also provides a battery device 2, which includes a plurality of battery cells 6 provided in any of the above embodiments.
[0158] According to some embodiments of this application, this application also provides an electrical device, which includes a battery device 2 of any of the above embodiments, the battery device 2 being used to provide electrical energy.
[0159] This application provides a battery cell 6, which includes an electrode assembly 10, a housing 20, and a first electrode lead-out 30. The first electrode lead-out 30 is disposed in the housing 20. The electrode assembly 10 is housed within the housing 20. The electrode assembly 10 includes a main body 11 and a first tab 12. The first tab 12 includes a first tab layer group 12a and a second tab layer group 12b. The first tab layer group 12a includes a plurality of stacked first tab layers 121, and the second tab layer group 12b includes a plurality of stacked second tab layers 122. Both the first tab layers 121 and the second tab layers 122 extend from the end of the main body 11 facing the first electrode lead-out 30. At least a portion of the first tab layer group 12a is located between the second tab layer group 12b and the first electrode lead-out 30, and is welded to the second tab layer group 12b and the first electrode lead-out 30. The first tab layer 121 has a first free end 1211 away from the main body 11, and the second tab layer 122 extends beyond the first free end 1211 of the first tab layer 121 along the extending direction of the first tab layer 121.
[0160] Each second tab layer 122 extends from the main body 11 by the same length, and each first tab layer 121 extends from the main body 11 by the same length. The length of the first tab layer 121 extending from the main body 11 is L1, and the length of the second tab layer 122 extending from the main body 11 is L2, where 10mm ≥ L2 - L1 ≥ 3mm.
[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A battery cell, characterized by, The battery cell comprises: a housing; a first electrode lead-out piece arranged in the housing; and an electrode assembly accommodated in the housing, the electrode assembly comprising a main body portion and a first tab, the first tab comprising a first tab layer group and a second tab layer group, the first tab layer group comprising a plurality of first tab layers arranged in a stack, the second tab layer group comprising a plurality of second tab layers arranged in a stack, the first tab layers and the second tab layers each extending from an end portion of the main body portion toward the first electrode lead-out piece; at least part of the first tab layer group is located between the second tab layer group and the first electrode lead-out piece, and is welded to the second tab layer group and the first electrode lead-out piece; the first tab layer has a first free end away from the main body portion, and at least part of the second tab layer exceeds the first free end of each first tab layer in the extension direction of the first tab layer.
2. The battery cell according to claim 1, wherein in the extension direction, the second tab layer adjacent to the first tab layer group exceeds the first free end of each first tab layer.
3. The battery cell according to claim 1 or 2, wherein the second tab layer has a second free end away from the main body portion, and in adjacent two second tab layers, the second tab layer closer to the first tab layer group exceeds the second free end of the other second tab layer in the extension direction.
4. The battery cell according to any one of claims 1-3, wherein in the extension direction, the first free ends of the plurality of first tab layers are flush.
5. The battery cell according to any one of claims 1-4, wherein the direction in which the second tab layer exceeds the first tab layer is parallel to the thickness direction of the battery cell, and the second tab layer is away from the median plane of the battery cell in the thickness direction.
6. The battery cell according to claim 5, wherein in the thickness direction, the distance between the second tab layer closest to the median plane and the first free end of the first tab layer closest to the median plane is d, and 5mm≥d≥3mm.
7. The battery cell according to any one of claims 1-6, wherein in the extension direction of the first tab layer, each second tab layer exceeds the first free end of all the first tab layers.
8. The battery cell according to any one of claims 1-7, wherein the length of each second tab layer extending from the main body portion is the same, and the length of each first tab layer extending from the main body portion is the same; or the length of the second tab layer extending from the main body portion is greater than the length of the first tab layer extending from the main body portion.
9. The battery cell according to claim 8, wherein the length of the first tab layer extending from the main body portion is L1, and the length of the second tab layer extending from the main body portion is L2, and 10mm≥L2-L1≥3mm. 10. The battery cell according to any one of claims 1-9, characterized in that, The first tab layer group, the second tab layer group, and the first electrode lead are welded together to form a first welded part, and the first free end of each first tab layer is spaced apart from the first welded part.
11. The battery cell according to claim 10, characterized in that, A portion of each of the first tab layers surrounds the first weld portion.
12. The battery cell according to claim 10 or 11, characterized in that, Each of the first tab layers of the first tab layer group is welded to form a second welded portion, and each of the second tab layers of the second tab layer group is welded to form a third welded portion. Both the second welded portion and the third welded portion are connected to the first welded portion.
13. The battery cell according to claim 12, characterized in that, The second weld portion at least partially surrounds the first weld portion and is directly connected to the first weld portion; and / or, the third weld portion at least partially surrounds the first weld portion and is directly connected to the first weld portion.
14. A battery device characterized by comprising: It includes multiple battery cells according to any one of claims 1-13.
15. An electrical device, characterized by Includes the battery device according to claim 14, the battery device being used to provide electrical energy.