Battery cells, battery packs and electrical devices

Abstract

This application provides a battery cell, a battery device, and an electrical device. The battery cell includes a casing and an electrode assembly. The electrode assembly has a stacked structure and includes multiple electrode sheets stacked along the thickness direction. Each electrode sheet includes a main body and a tab located at the length end of the main body. The main body includes a current collector, and the tab is connected to the current collector. The internal resistance of the current collector ranges from 0.97 mΩ to 26.89 mΩ. By extending the tab from the length end of the main body, the volumetric energy density of the battery cell is increased. By setting the internal resistance range of the current collector to 0.97 mΩ to 26.89 mΩ, the length, width, and thickness of the current collector can be adjusted according to its internal resistance to reduce heat generation and enable it to withstand larger currents, achieving high-rate charge and discharge, thereby improving the overcurrent capacity and charge / discharge performance of the battery cell.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] To achieve high volumetric energy density in battery cells, their length is often made quite long; for example, the blade battery's length is much greater than its width and thickness. However, these types of battery cells typically have tabs at their ends along the length, resulting in relatively weak current-carrying capacity. Utility Model Content

[0004] The purpose of this application is to provide a battery cell, a battery device, and an electrical device to improve the problem of weak overcurrent capacity of battery cells with end tabs in related technologies.

[0005] In a first aspect, embodiments of this application provide a single battery cell, comprising:

[0006] The outer shell has a length direction, a width direction and a thickness direction, the length of the outer shell is greater than or equal to the width of the outer shell, and the width of the outer shell is greater than or equal to the thickness of the outer shell;

[0007] The electrode assembly has a stacked structure and is housed in the housing. The electrode assembly includes multiple electrodes stacked along the thickness direction. Each electrode includes a main body and tabs located at the ends of the main body along the length direction. The main body includes a current collector and active material layers located on both sides of the current collector along the thickness direction. The tabs are connected to the current collector, and the internal resistance of the current collector ranges from 0.97mΩ to 26.89mΩ.

[0008] In the technical solution of this application embodiment, the electrode assembly uses a stacked structure, and the performance of each layer of electrode sheets in the thickness direction of the battery is well balanced. The tabs are led out at the ends of the main body of the electrode sheet in the length direction to improve the volumetric energy density of the battery cell. The internal resistance range of the current collector of the electrode sheet is set to 0.97mΩ-26.89mΩ. The length, width and thickness of the current collector can be adjusted according to the internal resistance of the current collector to reduce the heat generation of the current collector, so that it can withstand a larger current, thereby realizing high-rate charging and discharging, and improving the overcurrent capacity and charging and discharging performance of the battery cell.

[0009] In some embodiments, the current collector includes a negative current collector, the internal resistance of which ranges from 1.12 mΩ to 26.89 mΩ.

[0010] The above technical solution sets the internal resistance range of the negative electrode current collector to 1.12mΩ-26.89mΩ, thereby adjusting the length, width and thickness of the negative electrode current collector, reducing the heat generation of the negative electrode current collector, and enabling it to withstand a larger current, thereby improving the overcurrent capacity and charge / discharge performance of the battery cell.

[0011] In some embodiments, the current collector includes a negative electrode current collector with a width of W1, a thickness of T1, a length of L1, and a flow area of ​​S1 = W1 * T1, where S1 / L1 > 0.0006 mm.

[0012] Through the above technical solution, since the flow area S1 of the negative electrode current collector is the area of ​​the cross section perpendicular to its length direction, and the flow area S1 of the negative electrode current collector is positively correlated with the flow capacity, and the length L1 of the negative electrode current collector is positively correlated with the internal resistance of the negative electrode current collector, and correspondingly, the length L1 of the negative electrode current collector is positively correlated with the heat generated during the charging and discharging of the battery cell, setting the ratio of the flow area to the length of the negative electrode current collector to be greater than 0.0006mm can achieve a good balance between the flow capacity per unit length of the negative electrode current collector and the heat generated, thereby optimizing the energy density of the battery cell and improving the flow capacity and charge / discharge performance of the battery cell.

[0013] In some embodiments, 0.0008mm <S1 / L1<0.001mm。

[0014] By using the above technical solution and setting the range of the ratio of the current-flow area to the length of the negative electrode current collector, the current-flow capacity and heat generation per unit length of the negative electrode current collector can be better optimized, thereby further optimizing the energy density of the battery cell and improving the current-flow capacity and charge / discharge performance of the battery cell.

[0015] In some embodiments, the current collector includes a negative current collector with a thickness greater than or equal to 4.5 μm.

[0016] By using the above technical solution, the thickness of the negative electrode current collector is set to be greater than or equal to 4.5 μm, so that the negative electrode current collector has high structural strength and current carrying capacity, thereby enabling the battery cell to have high structural strength and current carrying capacity.

[0017] In some embodiments, the thickness of the negative electrode current collector ranges from 5 μm to 8 μm.

[0018] By using the above technical solution, the thickness range of the negative electrode current collector is selected to be 5μm-8μm, which can not only give the negative electrode current collector good structural strength and current carrying capacity, but also enable the battery cell to have a high energy density.

[0019] In some embodiments, the current collector includes a positive current collector, the internal resistance of which is within the range of [specific values ​​to be filled in].

[0020] 0.97mΩ-19.57mΩ.

[0021] By using the above technical solution, the internal resistance range of the positive electrode current collector is set to 0.97mΩ-19.57mΩ, so as to adjust the length, width and thickness of the positive electrode current collector, reduce the heat generation of the positive electrode current collector, and enable it to withstand a larger current, thereby improving the overcurrent capacity and charge and discharge performance of the battery cell.

[0022] In some embodiments, the current collector includes a positive current collector with a width of W2, a thickness of T2, a length of L2, and a flow area of ​​S2 = W2 * T2, where S2 / L2 > 0.0014 mm.

[0023] Through the above technical solution, since the current-flow area S2 of the positive electrode current collector is the area of ​​the cross section perpendicular to its length direction, and the current-flow area S2 of the positive electrode current collector is positively correlated with the current-flow capacity, and the length L2 of the positive electrode current collector is positively correlated with the internal resistance of the positive electrode current collector, correspondingly, the length L2 of the positive electrode current collector is positively correlated with the heat generated during the charging and discharging of the battery cell, by setting the ratio of the current-flow area to the length of the positive electrode current collector to be greater than 0.0014mm, a good balance can be achieved between the current-flow capacity per unit length of the positive electrode current collector and the heat generated, so as to optimize the energy density of the battery cell and improve the current-flow capacity and charge-discharge performance of the battery cell.

[0024] In some embodiments, 0.0017mm <S2 / L2<0.0022mm。

[0025] By using the above technical solution, and setting the range of the ratio of the current-flow area to the length of the positive current collector, the current-flow capacity and heat generation per unit length of the positive current collector can be better optimized, thereby further optimizing the energy density of the battery cell and improving the current-flow capacity and charge / discharge performance of the battery cell.

[0026] In some embodiments, the current collector includes a positive current collector with a thickness greater than or equal to 10 μm.

[0027] By using the above technical solution, the thickness of the positive electrode current collector is set to be greater than or equal to 10μm, so that the positive electrode current collector has high structural strength and current carrying capacity, thereby enabling the battery cell to have high structural strength and current carrying capacity.

[0028] In some embodiments, the thickness of the positive current collector ranges from 13 μm to 15 μm.

[0029] By using the above technical solution, the thickness range of the positive electrode current collector is selected to be 13μm-15μm, which can not only give the positive electrode current collector good structural strength and current carrying capacity, but also enable the battery cell to have a high energy density.

[0030] In some embodiments, the length of the housing ranges from 100mm to 400mm; and / or, the width of the housing ranges from 60mm to 150mm; and / or, the thickness of the housing ranges from 20mm to 80mm.

[0031] By using the above technical solutions, the length of the outer casing can be set to 100mm-400mm. This allows for a larger capacity of the battery cell while keeping the internal resistance of the current collector relatively small, enabling it to withstand a larger current and generate less heat. This, in turn, enables high-rate charging and discharging, thereby improving the overcurrent capacity and charging and discharging performance of the battery cell.

[0032] By using the above technical solutions, the outer casing can be set to a width of 60mm-150mm, which can balance the capacity and heat dissipation performance of the battery cells, giving the battery cells a higher volumetric energy density and better charge and discharge performance.

[0033] By using the above technical solutions, the outer casing can be set to a thickness of 20mm-80mm, which can balance the structural strength, capacity, and heat dissipation performance of the battery cell, giving the battery cell a high volumetric energy density, good structural strength, and good charge and discharge performance.

[0034] In some embodiments, the difference between the length of the housing and the length of the electrode ranges from 8 mm to 24 mm.

[0035] The above technical solution facilitates the installation of electrode sheets in the casing and also facilitates the formation of space for the electrode tabs between the current collector and the side wall of the casing along its length, enabling the battery cell to have a high volumetric energy density.

[0036] In some embodiments, the difference between the width of the housing and the width of the electrode ranges from 1.7 mm to 3.3 mm.

[0037] The above technical solution facilitates the installation of the electrode in the casing and allows the electrode to have a large filling rate in the width direction of the casing, resulting in a high volumetric energy density for the battery cell.

[0038] Secondly, embodiments of this application provide a battery device, including a battery cell as described in the above embodiments.

[0039] Thirdly, embodiments of this application provide an electrical device, including a battery cell or a battery device as described in the above embodiments, wherein the battery cell or battery device is used to store or provide electrical energy.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies 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.

[0042] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0043] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0044] Figure 3 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0045] Figure 4 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0046] Figure 5 This is a schematic diagram of the structure of the electrode assembly in some embodiments of this application;

[0047] Figure 6 This is a cross-sectional view of the electrode assembly in some embodiments of this application;

[0048] Figure 7 This is a front view structural diagram of the electrode assembly of some embodiments of this application;

[0049] Figure 8 This is a schematic diagram of the negative electrode sheet in some embodiments of this application;

[0050] Figure 9 This is a schematic diagram of the structure of the positive electrode sheet in some embodiments of this application;

[0051] Figure 10 This is a front view structural schematic diagram of the electrode assembly of some other embodiments of this application.

[0052] The main markings in the attached figures are as follows:

[0053] 11. Vehicle; 111. Controller; 112. Motor;

[0054] 200. Battery assembly; 20. Housing; 201. First housing; 202. Second housing;

[0055] 300. Battery cell; 31. Electrode assembly; 310. Electrode sheet; 311. Main body; 3111. Current collector; 3112. Active material layer; 3101. Positive electrode sheet; 31011. Positive current collector; 31012. Positive active material layer; 3102. Negative electrode sheet; 31021. Negative current collector; 31022. Negative active material layer; 312. Tab; 3121. Positive tab; 31 22. Negative electrode tab; 313. Diaphragm; 32. Outer shell; 321. Housing; 3210. Opening; 322. End cap; 323. Pressure relief mechanism; 324. Injection port; 325. Isolator; 33. Electrode terminal; 331. Positive terminal; 332. Negative terminal; 34. Adapter piece; 341. Positive adapter piece; 342. Negative adapter piece; 35. Insulating film; 36. Support plate; 361. Score;

[0056] X: length direction; Z: width direction; Y: thickness direction. Detailed Implementation

[0057] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0058] 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, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0059] In the description of the embodiments of this application, technical terms such as "first" and "second" 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. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0060] 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 in any suitable manner.

[0061] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0062] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0063] 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 have an "or" relationship.

[0064] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "Several" means one or more, unless otherwise explicitly specified.

[0065] In the description of the embodiments of this application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0066] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the 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.

[0067] In the description of the embodiments of this application, unless otherwise expressly specified and limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on or indirectly on the other element. When an element is referred to as "connected to" another element, it may be directly connected to or indirectly connected to the other element.

[0068] In the description of the embodiments in this application, unless otherwise expressly specified and limited, the technical term "proximity" refers to being close in location. For example, among three components A1, A2, and B, the distance between A1 and B is greater than the distance between A2 and B. Therefore, A2 is closer to B than A1, meaning A2 is adjacent to B, or B is adjacent to A2. Similarly, when there are multiple components C, namely C1, C2, ..., C... N If one of the C components, such as C2, is closer to the B component than the other C components, then B is adjacent to C2, or C2 is adjacent to B.

[0069] To improve the energy density of individual battery cells, "blade batteries" are currently widely used. Blade batteries are battery cells with a length greater than or equal to their width, and a thickness less than or equal to their width, with tabs extending from their longitudinal ends. Due to their longer length, blade batteries have a larger capacity, thus increasing their energy density. However, this type of battery cell with tabs at the ends has a longer current transmission path within the electrodes, leading to greater heat generation when carrying high currents. To ensure battery cell safety and prevent thermal runaway, the current flowing through the cell is often set relatively low, resulting in weaker overcurrent capacity and affecting the cell's charge and discharge performance.

[0070] Based on the above considerations, in order to improve the weak current-carrying capacity of battery cells with end tabs in related technologies, this application provides a battery cell that improves the volumetric energy density of the battery cell by extending tabs from the end of the main body along its length. Since the size of the current collector directly determines the size of the electrode, and the current-carrying capacity of the current collector directly determines the current-carrying capacity of the electrode, the current-carrying capacity of the electrode directly affects the overall current-carrying capacity and charge / discharge performance of the battery cell. By setting the internal resistance range of the current collector to 0.97mΩ-26.89mΩ, the length, width, and thickness of the current collector can be adjusted according to its internal resistance to reduce heat generation and enable it to withstand larger currents. This allows for high-rate charge / discharge, thereby improving the current-carrying capacity and charge / discharge performance of the battery cell, such as enabling the battery cell to achieve charge / discharge rates above 4C.

[0071] 4C charging refers to a battery cell being fully charged in a quarter of an hour (15 minutes). "C" represents the charging rate, which is the ratio between the charging current and the rated capacity (Ah) of the battery cell. The higher the number, the faster the charging speed. For example, 2C charging takes 30 minutes, while 4C charging only takes 15 minutes.

[0072] 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.

[0073] 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.

[0074] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0075] For ease of explanation, an electrical device is provided in one embodiment of this application, which is illustrated using a vehicle as an example.

[0076] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle 11 provided in some embodiments of this application. The vehicle 11 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 electric vehicles, etc. A battery device 200 is provided inside the vehicle 11, and the battery device 200 can be located at the bottom, front, or rear of the vehicle 11. The battery device 200 can be used to power the vehicle 11; for example, the battery device 200 can serve as the operating power source for the vehicle 11. The vehicle 11 may also include a controller 111 and a motor 112. The controller 111 is used to control the battery device 200 to supply power to the motor 112, for example, to meet the power needs of the vehicle 11 during starting, navigation, and driving.

[0077] In some embodiments, the battery device 200 can not only serve as the operating power source for the vehicle 11, but also as the driving power source for the vehicle 11, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 11.

[0078] Please refer to Figure 2 This application provides a battery device 200. The battery device 200 may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 300, which are connected in series, parallel, or mixed connection via a busbar.

[0079] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 300.

[0080] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 300 together. As another example, a battery module can be formed by bundling multiple battery cells 300 together with cable ties.

[0081] In some embodiments, the battery device 200 may be a battery pack, which includes a housing 20 and one or more individual battery cell assemblies housed within the housing 20.

[0082] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing 20 by fixing the battery module in the housing 20.

[0083] As an example, the battery cell assembly can also be housed in the housing 20 by directly fixing multiple battery cells 300 to the housing 20.

[0084] In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, which are fastened together to form a closed space inside the housing 20 to accommodate the battery cell 300. Here, "closed" refers to covering or shutting off, and can be either sealed or unsealed. The second housing 202 may be a hollow structure with one open end, and the first housing 201 may be a plate-like structure, covering the open side of the second housing 202. The first housing 201 may be the top cover or bottom plate of the housing 20. Alternatively, the first housing 201 and the second housing 202 may both be hollow structures with one open end, with the open side of the first housing 201 covering the open side of the second housing 202.

[0085] In some embodiments, the housing 20 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to opposite sides of the frame, thereby forming a closed space inside the housing 20 to accommodate the battery cells 300. The frame refers to a portion of the structure forming the peripheral sidewalls of the housing 20, the top cover refers to a plate-like structure forming the top of the housing 20, and the bottom plate refers to a plate-like structure forming the bottom of the housing 20.

[0086] In some embodiments, the housing 20 may be part of the vehicle's chassis structure. For example, a portion of the housing 20 may be at least a portion of the vehicle's floor, or a portion of the housing 20 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0087] Please see Figures 3 to 10 According to some embodiments of this application, a battery cell 300 is provided, including a housing 32 and an electrode assembly 31. The housing 32 has a length direction X, a width direction Z, and a thickness direction Y. The length L of the housing 32 is greater than or equal to the width W of the housing 32, and the width W of the housing 32 is greater than or equal to the thickness T of the housing 32. The electrode assembly 31 is disposed in the housing 32 and has a stacked structure. The electrode assembly 31 includes a plurality of electrode sheets 310 stacked along the thickness direction Y. Each electrode sheet 310 includes a main body portion 311 and a tab 312 disposed at the end of the main body portion 311 along the length direction X. The main body portion 311 includes a current collector 3111 and active material layers 3112 disposed on both sides of the current collector 3111 along the thickness direction Z. The tab 312 is connected to the current collector 3111. The internal resistance of the current collector 3111 ranges from 0.97mΩ to 26.89mΩ.

[0088] The outer casing 32 refers to the structure used to provide a accommodating space to accommodate the electrode assembly 31 and to support and protect the electrode assembly 31.

[0089] Electrode assembly 31 is a component in battery cell 300 that stores and releases electrical energy. Electrode assembly 31 includes electrode plates 310, which are divided into positive electrode plates 3101 and negative electrode plates 3102. Electrode assembly 31 mainly operates by the movement of metal ions between the positive electrode plate 3101 and the negative electrode plate 3102. As an example, battery cell 300 may include one or more electrode assemblies 31, which are also referred to as bare cells. When there are multiple electrode assemblies 31, they are connected in parallel.

[0090] The electrode assembly 31 is disposed in the housing 32 so as to support and protect the electrode assembly 31 through the housing 32.

[0091] Multi-story refers to a number of floors with two or more floors. Multiple refers to a number of two or more floors.

[0092] The electrode assembly 31 includes multilayer electrode sheets 310 stacked along the thickness direction Y, meaning that the multilayer electrode sheets 310 are stacked along the thickness direction Y.

[0093] The positive electrode sheet 3101 includes a positive current collector 31011 and a positive active material layer 31012. The positive active material layer 31012 is coated on the surface of the positive current collector 31011. The portion of the positive current collector 31011 not coated with the positive active material layer 31012 protrudes from the portion coated with the positive active material layer 31012. The portion not coated with the positive active material layer 31012 serves as the positive electrode tab 3121, or a metal conductor can be welded onto the positive current collector 31011 and led out to serve as the positive electrode tab 3121. Taking a lithium-ion battery as an example, the material of the positive current collector 31011 can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode 3102 includes a negative electrode current collector 31021 and a negative electrode active material layer 31022. The negative electrode active material layer 31022 is coated on the surface of the negative electrode current collector 31021. The portion of the negative electrode current collector 31021 not coated with the negative electrode active material layer 31022 protrudes beyond the portion coated with the negative electrode active material layer 31022. This uncoated portion serves as a negative electrode tab 3122. Alternatively, a metal conductor can be soldered onto the negative electrode current collector 31021 and led out to serve as a negative electrode tab 3122. The material of the negative electrode current collector 31021 can be copper, and the negative electrode active material can be carbon or silicon, etc. The positive electrode current collector 31011 and the negative electrode current collector 31021 are collectively referred to as current collector 3111. The positive electrode tab 3121 and the negative electrode tab 3122 are collectively referred to as tab 312. The negative electrode active material layer 31022 and the positive electrode active material layer 31021 are collectively referred to as the active material layer 3112.

[0094] In a stacked structure, tabs 312 are typically led out from the current collector 3111. The positive electrode 3101, negative electrode 3102, and separator 313 are arranged in the order of positive electrode 3101 – separator 313 – negative electrode 3102 – separator 313, and stacked layer by layer to form a stacked battery cell. Alternatively, the separator 313 can be cut and directly stacked as a single sheet, or it can be stacked in a Z-shaped fold without cutting the separator 313. The separator 313 can be made of materials such as PP (Polypropylene) or PE (Polyethylene). The separator 313 is an insulating film placed between the positive electrode 3101 and the negative electrode 3102. Its main function is to isolate the positive and negative electrodes and prevent electrons in the battery from passing freely, thus preventing short circuits, while allowing ions in the electrolyte to pass freely between the positive and negative electrodes to form a circuit. In some embodiments, the electrode assembly 31 may also not include the separator 313, such as some types of solid-state batteries that may not have a separator.

[0095] The main body 311 is the main part of the electrode 310. The main body 311 includes a current collector 3111 and an active material layer 3112, the active material layer 3112 being disposed on the side of the current collector 3111 along the thickness direction Y. As an example, the active material layer 3112 is disposed on both sides of the current collector 3111 in the thickness direction Y to improve the energy density of the battery cell 300.

[0096] The tab 312 is used in the electrode assembly 31 to connect to an external circuit, allowing current to flow through the main body 311 during charging and discharging. The tab 312 includes a positive tab 3121 and a negative tab 3122, which are used to connect to the positive and negative terminals of the external circuit, respectively. The positive tab 3121 and the negative tab 3122 can be located on the same side of the main body 311, or they can be located on different sides of the main body 311, such as on opposite sides of the main body 311.

[0097] The provision of a tab 312 at one end of the main body 311 along the length direction X means that a tab 312 is provided at one end of the main body 311 along the length direction X, or that tabs 312 are provided at opposite ends of the main body 311 along the length direction X.

[0098] The tab 312 can be connected to the current collector 3111. The tab 312 and the current collector 3111 can be made separately and then welded together. Alternatively, the tab 312 and the current collector 3111 can be made as a single piece, such as one part of a metal sheet serving as the current collector 3111 and the other part serving as the tab 312.

[0099] The electrode assembly 31 uses a stacked structure, and the performance of each layer of electrode 310 in the thickness direction Y of the battery is well balanced. Moreover, the filling rate in the casing 32 is high, which makes the battery cell 300 have a high volumetric energy density.

[0100] The battery cell 300 has a length direction, a width direction, and a thickness direction, such as Figure 3 As shown, direction X represents the length of the battery cell 300, direction Z represents the width of the battery cell 300, and direction Y represents the thickness of the battery cell 300. Since the outer casing 32 defines the shape of the battery cell 300, the length directions of the outer casing 32 and the electrode assembly 31 are consistent with the length direction X of the battery cell 300; the width directions of the outer casing 32 and the electrode assembly 31 are consistent with the width direction Z of the battery cell 300; and the thickness directions of the outer casing 32 and the electrode assembly 31 are consistent with the thickness direction Y of the battery cell 300. The length direction of the electrode 310 is consistent with the length direction X of the battery cell 300; the width direction of the electrode 310 is consistent with the width direction Z of the battery cell 300; and the thickness direction of the electrode 310 is consistent with the thickness direction Y of the battery cell 300.

[0101] The length L of the outer casing 32 being greater than or equal to the width W of the outer casing 32 means that the dimension of the outer casing 32 along the length direction X is greater than or equal to the dimension of the outer casing 32 along the width direction Z. The width W of the outer casing 32 being greater than or equal to the thickness T of the outer casing 32 means that the dimension of the outer casing 32 along the width direction Z is greater than or equal to the dimension of the outer casing 32 along the thickness direction Y.

[0102] The internal resistance of current collector 3111 refers to its DC internal resistance. 1 milliohm (mΩ) is 0.001 ohm.

[0103] The internal resistance of the current collector 3111 ranges from 0.97mΩ to 26.89mΩ, with specific values ​​such as 0.97mΩ, 1mΩ, 3mΩ, 5mΩ, 8mΩ, 10mΩ, 12mΩ, 14mΩ, 16mΩ, 18mΩ, 20mΩ, 22mΩ, 24mΩ, 26mΩ, and 26.89mΩ. The internal resistance of the current collector 3111 is directly proportional to its length, and inversely proportional to the area of ​​its cross-section perpendicular to its length direction X. The area of ​​the cross-section perpendicular to the length direction X is the product of the current collector 3111's width and thickness. The length and width of the current collector 3111 determine the area of ​​active material coated on it; a larger area of ​​active material coating results in a larger capacity for the corresponding battery cell 300. The thickness of the current collector 3111 determines the number of layers of current collector 3111 in the casing 32. The more layers, the larger the capacity of the battery cell 300. Based on the internal resistance range of the current collector 3111, the length, width, and thickness of the current collector 3111 can be set so that the current collector 3111 can withstand a larger current and generate less heat, thereby enabling the battery cell 300 to have good charge and discharge performance.

[0104] In the technical solution of this application embodiment, by leading out tabs 312 from the end of the main body portion 311 of the electrode 310 in the length direction X, the volumetric energy density of the battery cell 300 is improved; and by setting the internal resistance range of the current collector 3111 of the electrode 310 to 0.97mΩ-26.89mΩ, the length, width and thickness of the current collector 3111 can be adjusted according to the internal resistance of the current collector 3111 to reduce the heat generation of the current collector 3111, so that it can withstand a larger current, thereby achieving high-rate charging and discharging, and improving the overcurrent capacity and charging and discharging performance of the battery cell 300.

[0105] In some embodiments, please refer to Figures 6 to 10 The current collector 3111 includes a negative current collector 31021, and the internal resistance of the negative current collector 31021 ranges from 1.12mΩ to 26.89mΩ.

[0106] The negative electrode current collector 31021 refers to the current collector 3111 in the negative electrode 3102. The internal resistance of the negative electrode current collector 31021 ranges from 1.12mΩ to 26.89mΩ, such as 1.12mΩ, 1.2mΩ, 3mΩ, 5mΩ, 8mΩ, 10mΩ, 12mΩ, 14mΩ, 16mΩ, 18mΩ, 20mΩ, 22mΩ, 24mΩ, 26mΩ, and 26.89mΩ.

[0107] By setting the internal resistance range of the negative electrode current collector 31021 to 1.12mΩ-26.89mΩ, the length, width and thickness of the negative electrode current collector 31021 can be adjusted according to the overall size of the battery cell 300 to balance the current carrying capacity, heat generation and overall size of the negative electrode current collector 31021, so that the battery cell 300 using the negative electrode current collector 31021 can have higher volumetric energy density and better charge and discharge performance.

[0108] Through the above technical solution, the internal resistance range of the negative electrode current collector 31021 is set to 1.12mΩ-26.89mΩ, so as to adjust the length, width and thickness of the negative electrode current collector 31021, reduce the heat generation of the negative electrode current collector 31021, and enable it to withstand a larger current, thereby improving the overcurrent capacity and charge and discharge performance of the battery cell 300.

[0109] In some embodiments, please refer to Figures 6 to 10 The current collector 3111 includes a negative current collector 31021. The width of the negative current collector 31021 is W1, the thickness of the negative current collector 31021 is T1, the length of the negative current collector 31021 is L1, and the flow area of ​​the negative current collector 31021 is S1=W1*T1, S1 / L1>0.0006mm.

[0110] The width W1 of the negative electrode current collector 31021 refers to the dimension of the negative electrode current collector 31021 along the width direction Z.

[0111] The thickness T1 of the negative electrode current collector 31021 refers to the dimension of the negative electrode current collector 31021 along the thickness direction Y.

[0112] The length L1 of the negative electrode current collector 31021 refers to the dimension of the negative electrode current collector 31021 along the length direction X.

[0113] The flow area S1 of the negative electrode current collector 31021 refers to the cross-sectional area of ​​the negative electrode current collector 31021 along the direction perpendicular to the length X.

[0114] S1 / L1 > 0.0006 mm, that is, the ratio of the current-carrying area S1 of the negative electrode current collector 31021 to the length L1 of the negative electrode current collector 31021 is greater than 0.0006 mm. For example, the ratio of the current-carrying area S1 of the negative electrode current collector 31021 to the length L1 of the negative electrode current collector 31021 is 0.00061 mm, 0.00065 mm, 0.00067 mm, 0.0007 mm, 0.00072 mm, 0.00074 mm, 0.00076 mm, 0.00078 mm, 0.0008 mm, 0.00082 mm, 0.00084 mm, 0.00086 mm, 0.00088 mm, 0.0009 mm, 0.00092 mm, 0.00094 mm, 0.00096 mm, 0.00098 mm, 0.001 mm, 0.0011 mm, 0.0012 mm, 0.0013 mm, 0.0014 mm, 0.0015 mm, etc.

[0115] Through the above technical solution, since the current-carrying area S1 of the negative electrode current collector 31021 is the area of the cross-section along the direction X perpendicular to its length, and the current-carrying area S1 of the negative electrode current collector 31021 is positively correlated with the current-carrying capacity, and the length L1 of the negative electrode current collector 31021 is positively correlated with the internal resistance of the negative electrode current collector 31021. Correspondingly, the length L1 of the negative electrode current collector 31021 is positively correlated with the heat generation during charging and discharging of the battery cell 300. Setting the ratio of the current-carrying area S1 to the length L1 of the negative electrode current collector 31021 to be greater than 0.0006 mm can achieve a good balance between the current-carrying capacity per unit length and the heat generation of the negative electrode current collector 31021, so as to optimize the energy density of the battery cell 300 and improve the current-carrying capacity and charge-discharge performance of the battery cell 300.

[0116] In some embodiments, 0.0008 mm < S1 / L1 < 0.001 mm, that is, the ratio of the current-carrying area S1 of the negative electrode current collector 31021 to the length L1 of the negative electrode current collector 31021 is greater than 0.0008 mm and less than 0.001 mm.

[0117] Through the above technical solution, setting the range of the ratio of the current-carrying area S1 to the length L1 of the negative electrode current collector 31021 can better optimize the current-carrying capacity per unit length and the heat generation of the negative electrode current collector 31021, so as to further optimize the energy density of the battery cell 300 and improve the current-carrying capacity and charge-discharge performance of the battery cell 300.

[0118] In some embodiments, please refer to Figures 6 to 10 , the current collector 3111 includes a negative electrode current collector 31021, and the thickness T1 of the negative electrode current collector 31021 is greater than or equal to 4.5 μm.

[0119] The thickness T1 of the negative electrode current collector 31021 is greater than or equal to 4.5 micrometers (4.5 μm). For example, the thickness T1 of the negative electrode current collector 31021 can be 4.5 μm, 4.8 μm, 5 μm, 5.2 μm, 5.5 μm, 5.8 μm, 6 μm, 6.2 μm, 6.5 μm, 6.8 μm, 7 μm, 7.2 μm, 7.5 μm, 7.8 μm, 8 μm, 8.2 μm, 8.5 μm, 8.8 μm, 9 μm, 9.2 μm, 9.5 μm, 9.8 μm, 10 μm, etc.

[0120] Through the above technical solution, the thickness T1 of the negative electrode current collector 31021 is set to be greater than or equal to 4.5μm, so that the negative electrode current collector 31021 has high structural strength and current carrying capacity, thereby enabling the battery cell 300 to have high structural strength and current carrying capacity.

[0121] In some embodiments, the thickness T1 of the negative electrode current collector 31021 ranges from 5 μm to 8 μm.

[0122] By using the above technical solution, the thickness T1 of the negative electrode current collector 31021 is selected to be in the range of 5μm-8μm. This not only enables the negative electrode current collector 31021 to have good structural strength and current carrying capacity, but also enables the battery cell 300 to have a high energy density.

[0123] In some embodiments, the current collector 3111 includes a positive current collector 31011, the internal resistance of which is in the range of 0.97mΩ-19.57mΩ.

[0124] The positive current collector 31011 refers to the current collector 3111 in the positive electrode 3101. The internal resistance of the positive current collector 31011 ranges from 0.97mΩ to 19.57mΩ, such as 0.97mΩ, 1mΩ, 1.02mΩ, 1.05mΩ, 1.08mΩ, 1.1mΩ, 1.12mΩ, 1.2mΩ, 3mΩ, 5mΩ, 8mΩ, 10mΩ, 12mΩ, 14mΩ, 16mΩ, 18mΩ, 19mΩ, and 19.57mΩ.

[0125] By setting the internal resistance range of the positive current collector 31011 to 0.97mΩ-19.57mΩ, the length, width and thickness of the positive current collector 31011 can be adjusted according to the overall size of the battery cell 300 to balance the current carrying capacity, heat generation and overall size of the positive current collector 31011, so that the battery cell 300 using the positive current collector 31011 can have higher volumetric energy density and better charge and discharge performance.

[0126] Through the above technical solution, the internal resistance range of the positive current collector 31011 is set to 0.97mΩ-19.57mΩ, so as to adjust the length, width and thickness of the positive current collector 31011, reduce the heat generation of the positive current collector 31011, and enable it to withstand a larger current, thereby improving the overcurrent capacity and charge and discharge performance of the battery cell 300.

[0127] In some embodiments, please refer to Figures 6 to 10 The current collector 3111 includes a positive current collector 31011, the width of the positive current collector 31011 is W2, the thickness of the positive current collector 31011 is T2, the length of the positive current collector 31011 is L2, and the flow area of ​​the positive current collector 31011 is S2=W2*T2, S2 / L2>0.0014mm.

[0128] The width W2 of the positive current collector 31011 refers to the dimension of the positive current collector 31011 along the width direction Z.

[0129] The thickness T2 of the positive electrode current collector 31011 refers to the dimension of the positive electrode current collector 31011 along the thickness direction Y.

[0130] The length L2 of the positive electrode current collector 31011 refers to the dimension of the positive electrode current collector 31011 along the length direction X.

[0131] The flow area S2 of the positive electrode current collector 31011 refers to the cross-sectional area of ​​the positive electrode current collector 31011 along the length direction X.

[0132] S2 / L2>0.0014mm, meaning the ratio of the flow area S2 of the positive electrode current collector 31011 to the length L2 of the positive electrode current collector 31011 is greater than 0.0014mm. For example, the ratio of the flow area S2 of the positive electrode current collector 31011 to the length L2 of the positive electrode current collector 31011 is 0.0014mm, 0.00145mm, 0.0015mm, 0.00155mm, 0.0014 ...45mm, 0.00145mm, 0.00145mm, 0.00145mm, 0.00145mm, 0. 0.0016mm, 0.00165mm, 0.0017mm, 0.00175mm, 0.0018mm, 0.00185mm, 0.0019mm, 0.00195mm, 0.0020mm, 0.00205mm, 0.0021mm, 0.00215mm, 0.0022mm, 0.0022.5mm, 0.0023mm, etc.

[0133] Through the above technical solution, since the current-carrying area S2 of the positive electrode current collector 31011 is the area of ​​the cross section perpendicular to its length direction X, and the current-carrying area S2 of the positive electrode current collector 31011 is positively correlated with the current-carrying capacity, and the length L2 of the positive electrode current collector 31011 is positively correlated with the internal resistance of the positive electrode current collector 31011, correspondingly, the length L2 of the positive electrode current collector 31011 is positively correlated with the heat generation of the battery cell 300 during charging and discharging, by setting the ratio of the current-carrying area S2 to the length L2 of the positive electrode current collector 31011 to be greater than 0.0014mm, the current-carrying capacity per unit length of the positive electrode current collector 31011 and the heat generation can be well balanced, so as to optimize the energy density of the battery cell 300 and improve the current-carrying capacity and charge-discharge performance of the battery cell 300.

[0134] In some embodiments, 0.0017mm <S2 / L2<0.0022mm。

[0135] By setting the range of the ratio of the current-carrying area S2 to the length L2 of the positive current collector 31011 through the above technical solution, the current-carrying capacity and heat generation per unit length of the positive current collector 31011 can be better optimized, so as to further optimize the energy density of the battery cell 300 and improve the current-carrying capacity and charge-discharge performance of the battery cell 300.

[0136] In some embodiments, please refer to Figures 6 to 10 The current collector 3111 includes a positive current collector 31011, and the thickness T2 of the positive current collector 31011 is greater than or equal to 10 μm.

[0137] The thickness T2 of the negative electrode current collector 31021 is greater than or equal to 10 μm. For example, the thickness T2 of the negative electrode current collector 31021 can be 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 15.5 μm, 16 μm, 16.5 μm, 17 μm, etc.

[0138] Through the above technical solution, the thickness T2 of the positive electrode current collector 31011 is set to be greater than or equal to 10μm, so that the positive electrode current collector 31011 has high structural strength and current carrying capacity, thereby enabling the battery cell 300 to have high structural strength and current carrying capacity.

[0139] In some embodiments, please refer to Figures 6 to 10 The thickness T2 of the positive electrode current collector 31011 ranges from 13μm to 15μm.

[0140] By using the above technical solution, the thickness T2 of the positive electrode current collector 31011 is selected to be in the range of 13μm-15μm. This can give the positive electrode current collector 31011 good structural strength and current carrying capacity, and also give the battery cell 300 a high energy density.

[0141] In some embodiments, please refer to Figure 3 and Figure 4 The dimensions of the outer casing 32 along the length direction X range from 100 mm to 400 mm.

[0142] The dimension of the outer casing 32 along the length direction X also refers to the length L of the outer casing 32. The dimension of the outer casing 32 along the length direction X ranges from 100mm to 400mm, such as the length L of the outer casing 32 being 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 250mm, 280mm, 300mm, 320mm, 350mm, 380mm, 400mm, etc.

[0143] By setting the length of the outer casing 32 along the X direction to 100mm-400mm, the capacity of the battery cell 300 can be made larger, while the size of the electrode 310 is set smaller than that of the outer casing 32. Consequently, the length L of the outer casing 32 also limits the length range of the electrode 310. By setting the length range, the internal resistance of the current collector 3111 of the electrode 310 can be relatively small, so as to withstand a larger current and less heat generation, thereby achieving high-rate charging and discharging, and improving the overcurrent capacity and charging and discharging performance of the battery cell 300.

[0144] In some embodiments, please refer to Figure 3 and Figure 4 The dimensions of the outer casing 32 along the width direction Z range from 60mm to 150mm.

[0145] The dimension of the outer casing 32 along the width direction Z also refers to the width W of the outer casing 32. The dimension of the outer casing 32 along the width direction Z ranges from 60mm to 150mm, such as the length W of the outer casing 32, which can be 60mm, 80mm, 90mm, 100mm, 120mm, 120mm, 150mm, etc. Since the electrode assembly 31 has tabs 312 led out from its end along the length direction X, and correspondingly, the tabs 312 are located at the end of the outer casing 32 along the length direction X, a receiving space is provided at the end of the outer casing 32 along the length direction X to accommodate the tabs 312. The size of this receiving space is positively correlated with the width W and thickness T of the outer casing 32. That is, the larger the width W of the outer casing 32, the larger the size of the receiving space, and correspondingly, the larger the space occupied inside the outer casing 32. Setting the dimension of the outer casing 32 along the width direction Z to 60mm-150mm can balance the capacity of the battery cell 300 and the area size of the end of the battery cell 300 along the length direction X, so that the battery cell 300 has a higher volumetric energy density. In addition, the width of the outer casing 32 also determines the side area of ​​the battery cell 300. The electrode 310 is located in the outer casing 32. Accordingly, the size of the electrode 310 is smaller than the size of the outer casing 32. By setting the width range mentioned above, the internal resistance of the current collector 3111 of the electrode 310 can be set to be relatively small so as to withstand a larger current and a smaller heat generation, thereby achieving high-rate charging and discharging, and improving the overcurrent capacity and charging and discharging performance of the battery cell 300.

[0146] In some embodiments, please refer to Figure 3 and Figure 4 The outer shell 32 has a thickness Y dimension ranging from 20mm to 80mm.

[0147] The dimension of the outer casing 32 along the thickness direction Y also refers to the thickness T of the outer casing 32. The dimension of the outer casing 32 along the thickness direction Y ranges from 20mm to 80mm, such as the thickness T of the outer casing 32 being 20mm, 25mm, 30mm, 35mm, 40mm, 50mm, 60mm, 70mm, 80mm, etc. Since a receiving space is provided at the end of the outer casing 32 along the length direction X to accommodate the electrode tab 312, the size of this receiving space is positively correlated with the width W and thickness T of the outer casing 32. That is, the greater the thickness of the outer casing 32, the larger the size of this receiving space, and correspondingly, the larger the space occupied inside the outer casing 32. Furthermore, since the electrode assembly 31 is placed inside the outer casing 32, and the electrode plates 310 of the electrode assembly 31 are stacked along the thickness direction Y, the size range of the outer casing 32 also limits the thickness of the electrode assembly 31 and the range of the number of layers of the electrode plates 310.

[0148] By using the above technical solution, the outer casing 32 is set to a thickness Y dimension of 20mm-80mm, which can balance the structural strength, capacity, and heat dissipation performance of the battery cell 300, so that the battery cell 300 has a high volumetric energy density, good structural strength, and good charge and discharge performance.

[0149] In some embodiments, please refer to Figures 3 to 10 The difference between the length L of the outer shell 32 and the length of the electrode 310 is 8mm-24mm. That is to say, the length L of the outer shell 32 is 8mm-24mm longer than the length of the electrode 310. For example, the length of the outer shell 32 is 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm longer than the length of the electrode 310.

[0150] The difference between the length L of the outer casing 32 and the length of the electrode 310 is set to be 8mm-24mm. After subtracting the thickness of the sidewalls at both ends of the outer casing 32 in the length direction X, the electrode 310 can still be well placed in the outer casing 32, and a certain space is formed between the end face of the electrode 310 in the length direction X and the sidewall of the outer casing 32 in the length direction X to accommodate the tab 312. Moreover, the filling rate of the electrode 310 in the length direction X of the outer casing 32 can be higher, that is, the ratio of the length of the electrode 310 to the length L of the outer casing 32 is higher, so as to improve the volumetric energy density of the battery cell 300.

[0151] The above technical solution facilitates the installation of the electrode 310 in the housing 32, and also facilitates the formation of a space for the tab 312 to be accommodated between the current collector 3111 and the side wall of the housing 32 in the X direction of the length direction, so that the battery cell 300 has a high volumetric energy density.

[0152] In some embodiments, please refer to Figures 3 to 10 The difference between the width W of the outer shell 32 and the width of the electrode 310 ranges from 1.7mm to 3.3mm. That is to say, the width W of the outer shell 32 is 1.7mm to 3.3mm larger than the width of the electrode 310. For example, the width W of the outer shell 32 is 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, etc., larger than the width of the electrode 310.

[0153] By setting the difference between the width W of the outer casing 32 and the width of the electrode 310 to a range of 1.7mm-3.3mm, and subtracting the thickness of the sidewalls at both ends of the outer casing 32 in the width direction Z, the internal width of the outer casing 32 can still be greater than the width of the electrode 310, so that the electrode 310 can be placed inside the outer casing 32. In addition, the filling rate of the electrode 310 in the width direction Z of the outer casing 32 can be higher, that is, the ratio of the width of the electrode 310 to the width W of the outer casing 32 can be higher, thereby improving the volumetric energy density of the battery cell 300.

[0154] The above technical solution facilitates the installation of the electrode 310 in the housing 32, and enables the electrode 310 to have a large filling rate in the width direction Z of the housing 32, thereby enabling the battery cell 300 to have a high volumetric energy density.

[0155] In some embodiments, please refer to Figures 6 to 10 The area of ​​the negative electrode 3102 is larger than the area of ​​the positive electrode 3101. The area of ​​the negative electrode 3102 refers to the area formed by the length and width of the negative electrode 3102. The area of ​​the positive electrode 3101 refers to the area formed by the length and width of the positive electrode 3101.

[0156] During charging, lithium ions migrate from the positive electrode to the negative electrode and embed themselves in the negative electrode material. If the area of ​​the negative electrode 3102 is small, lithium ions will concentrate in a smaller space, easily leading to the formation of lithium dendrites (lithium metal deposition). Lithium dendrites not only reduce battery performance but may also penetrate the separator 313, causing a short circuit and posing a safety hazard. Increasing the area of ​​the negative electrode 3102 can disperse the embedding points of lithium ions and reduce the risk of lithium dendrite formation. In addition, during a full charge-discharge cycle, the active materials in the positive and negative electrode materials should participate in the reaction simultaneously. However, in reality, due to the presence of side reactions, the positive electrode material may reach saturation first and stop working, while the negative electrode still has unutilized active materials. By increasing the area of ​​the negative electrode 3102, more lithium ions can be effectively embedded in the negative electrode to a certain extent, thereby improving the overall energy density and utilization efficiency of the battery. Moreover, a larger negative electrode 3102 area helps to dissipate heat better, especially in high-power output or fast charging scenarios, which can effectively prevent local overheating and extend battery life. Furthermore, appropriately increasing the area of ​​the negative electrode 3102 can make the electrolyte more evenly distributed inside the battery, which is conducive to maintaining a stable ion conduction path and further improving the overall performance of the battery.

[0157] In some embodiments, please refer to Figures 6 to 10The width W1 of the negative electrode 3102 is greater than the width W2 of the positive electrode 3101. This not only makes it easier to set the area of ​​the negative electrode 3102 to be greater than the area of ​​the positive electrode 3101, but also reduces the formation of lithium dendrites on the side of the electrode 310 along the width direction Z.

[0158] In some embodiments, please refer to Figures 6 to 10 The length L1 of the negative electrode 3102 is greater than the length L2 of the positive electrode 3101. This not only makes it easier to set the area of ​​the negative electrode 3102 to be greater than the area of ​​the positive electrode 3101, but also reduces the formation of lithium dendrites on the side of the electrode 310 along the length direction X.

[0159] In some embodiments, please refer to Figures 6 to 10 The width W3 of the separator 313 is greater than the width W1 of the negative electrode 3102, so as to better protect the negative electrode 3102, reduce the risk of short circuit between the negative electrode 3102 and the positive electrode 3101, and also reduce the risk of short circuit between the negative electrode 3102 and the outer shell.

[0160] In some embodiments, please refer to Figures 6 to 10 The length L3 of the separator 313 is greater than the length L1 of the negative electrode 3102, so as to better protect the negative electrode 3102, reduce the risk of short circuit between the negative electrode 3102 and the positive electrode 3101, and also reduce the risk of short circuit between the negative electrode 3102 and the outer shell.

[0161] In some embodiments, please refer to Figure 3 and Figure 4 The housing 32 includes a housing 321 and an end cap 322. The electrode assembly 31 is installed in the housing 321 and the end cap 322 covers the housing 321.

[0162] End cap 322 refers to a component that covers the opening of housing 321 to isolate the internal environment of battery cell 300 from the external environment. The shape of end cap 322 can be adapted to the shape of housing 321 to fit onto housing 321. Optionally, end cap 322 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 322 is not easily deformed when subjected to compression and impact, so that battery cell 300 can have higher structural strength and improved reliability. The material of end cap 322 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application does not impose any special limitations on it.

[0163] The housing 321 is an assembly used to cooperate with the end cap 322 to form the internal environment of the battery cell 300, wherein the formed internal environment can accommodate the electrode assembly 31, electrolyte, and other components. The housing 321 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 321 can be determined according to the specific shape and size of the battery cell 300. The material of the housing 321 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application does not impose any special limitations on it.

[0164] In some embodiments, please refer to Figure 3 and Figure 4 The end cap 322 is provided at the end of the housing 321 in the length direction X, so that the tab 312 at the end of the electrode assembly 31 in the length direction X can be led out.

[0165] In some embodiments, please refer to Figure 3 and Figure 4 The end cap 322 is fitted with an isolator 325, which can be used to isolate the electrical connection components within the housing 321 from the end cap 322 to reduce the risk of short circuits. For example, the isolator 325 can be made of plastic, rubber, etc.

[0166] In some embodiments, please refer to Figure 3 and Figure 4 The outer casing 32 is provided with an injection hole 324. The injection hole 324 is a perforated structure used to inject electrolyte into the outer casing 32. After the electrode assembly 31 is manufactured, it needs to be installed in the casing 321 and electrolyte injected so that the electrode assembly 31 is immersed in the electrolyte, allowing it to fully absorb the electrolyte. The electrolyte can provide some active ions for use as conductive ions during the charging and discharging process; in addition, the electrolyte provides ion channels, or carriers, allowing ions to move freely within them to achieve electrical conduction between the electrodes. The outer casing 32 is provided with an injection hole 324 to allow electrolyte to be added into it.

[0167] As an example, the injection port 324 can be provided on the housing 321. Of course, the injection port 324 can also be provided on the end cap 322.

[0168] In some embodiments, please refer to Figure 3 and Figure 4 The outer casing 32 is equipped with a pressure relief mechanism 323, which is used to release internal pressure when the internal pressure or temperature of the battery cell 300 reaches a threshold. The pressure relief mechanism 323 can be a structure such as an explosion-proof valve or explosion-proof plate installed on the outer casing 32.

[0169] In some embodiments, please refer to Figure 3 and Figure 4The battery cell 300 includes electrode terminals 33, which are disposed on the housing 32 and connected to the tabs 312 of the electrode assembly 31. Electrode terminals 33 are conductive components disposed on the housing 32. They are connected to the tabs 312 of the electrode assembly 31 to output electrical energy from the battery cell 300 or to charge the battery cell 300. The battery cell 300 typically has two electrode terminals 33: a positive terminal 331 and a negative terminal 332. The positive terminal 331 is connected to the positive tab 3121 of the electrode assembly 31, and the negative terminal 332 is connected to the negative tab 3122 of the electrode assembly 31.

[0170] In some embodiments, please refer to Figure 3 and Figure 4 The battery cell 300 also includes two adapter pieces 34, each corresponding to one of the two electrode terminals 33. Each tab 312 is connected to its corresponding electrode terminal 33 via the adapter piece 34, facilitating a more secure connection between the tab 312 and the electrode terminal 33. The two adapter pieces 34 are a positive adapter piece 341 and a negative adapter piece 342. The positive adapter piece 341 connects the positive tab 3121 to the positive terminal 331, and the negative adapter piece 342 connects the negative tab 3122 to the negative terminal 332.

[0171] In some embodiments, please refer to Figure 3 and Figure 4 The battery cell 300 includes an insulating film 35 that surrounds the electrode assembly 31 to bind the electrode assembly 31, thereby facilitating its insertion into the housing 32. The insulating film 35 also protects the electrode assembly 31. The insulating film 35 can be made of insulating materials such as polypropylene or polyethylene to effectively insulate the electrode assembly 31 from the housing 32, reducing the risk of internal short circuits within the battery cell 300.

[0172] In some embodiments, please refer to Figure 3 and Figure 4 When the housing 32 includes an end cap 322, the electrode terminal 33 can be disposed on the end cap 322 so as to be connected to the tab 312 of the electrode assembly 31, and also to be easy to install on the housing 321.

[0173] In some embodiments, please refer to Figure 3 and Figure 4When end caps 322 are provided at both ends of the housing 321, tabs 312 can be led out from both ends of the main body 311 along the length X direction of the electrode assembly 31. For example, a positive tab 3121 can be led out from one end of the main body 311, and a negative tab 3122 can be led out from the other end. A positive terminal 331 is provided on one end cap 322, and a negative terminal 332 is provided on the other end cap 322. This allows for easy connection of the negative tab 3122 to the negative terminal 332 and the positive tab 3121 to the positive terminal 331, thus enabling the positive and negative terminals 331 and 332 to be led out from both ends of the housing 32. This structure allows for a larger dimension of the tabs 312 along the width Z direction, thereby improving the charging and discharging performance of the electrode assembly 31.

[0174] In some embodiments, please refer to Figure 3 and Figure 4 Alternatively, a positive electrode tab 3121 and a negative electrode tab 3122 can be simultaneously led out from one end of the main body 311. Correspondingly, a positive terminal 331 and a negative terminal 332 are provided on an end cap 322 to connect the positive electrode tab 3121 and the negative electrode tab 3122 of the electrode assembly 31.

[0175] In some embodiments, electrode terminals 33 may also be provided on other sidewalls of the housing 32, such as on the sidewalls in the width direction, to be connected to the corresponding tabs 312 of the electrode assembly 31.

[0176] In some embodiments, please refer to Figure 3 and Figure 4 The capacity C of a single 300 battery cell ranges from 5Ah to 250Ah.

[0177] The capacity C of a single 300 battery cell ranges from 5Ah to 250Ah. For example, the capacity C of a single 300 battery cell can be 5Ah, 10Ah, 15Ah, 20Ah, 30Ah, 40Ah, 50Ah, 60Ah, 80Ah, 100Ah, 120Ah, 150Ah, 180Ah, 200Ah, 220Ah, 250Ah, etc.

[0178] A larger capacity in the battery cell 300 allows for a larger electrode assembly 31 within the casing 32. With a fixed casing 32 size, a larger capacity in the battery cell 300 results in a higher volumetric density. This larger capacity also leads to a larger electrode assembly 31, which in the event of thermal runaway tends to generate more gas. Setting the capacity of the battery cell 300 to 5Ah-250Ah allows for a higher volumetric density, and also ensures that the gas generated during thermal runaway can flow effectively from the channel 301 to the pressure relief section 351 for discharge.

[0179] In some embodiments, please refer to Figure 3 and Figure 4 The outer shell 32 is made of aluminum, steel or titanium.

[0180] An aluminum shell refers to a shell structure made of aluminum or aluminum alloy.

[0181] A steel shell refers to a shell structure made of steel.

[0182] A titanium shell refers to a shell structure made of titanium metal or titanium alloy.

[0183] The outer casing 32 uses an aluminum casing, which is lightweight and low-cost. The outer casing 32 uses a steel casing, which has high structural strength and low cost. The outer casing 32 uses a titanium casing, which has high structural strength and good corrosion resistance.

[0184] In some embodiments, please refer to Figure 3 and Figure 4 The pressure resistance range of the connection between the end cap 322 and the housing 321 is 0.5 MPa to 5 MPa.

[0185] Pressure resistance refers to the maximum pressure an object can withstand without being destroyed.

[0186] The pressure resistance of the connection between the end cap 322 and the housing 321 refers to the maximum pressure that the connection between the end cap 322 and the housing 321 can withstand without being damaged when the housing 322 is filled with gas or liquid to increase the pressure in the housing 32.

[0187] The withstand pressure range of the connection between the end cap 322 and the housing 321 is 0.5MPa-5MPa. For example, the withstand pressure of the connection between the end cap 322 and the housing 321 can be 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, 5MPa, etc., to ensure that the battery cell 300 has good structural strength and airtightness.

[0188] In some embodiments, please refer to Figure 3 and Figure 4 The housing 32 includes a housing 321 and an end cap 322. An opening 3210 is provided at the end of the housing 321 along its length X direction, and the end cap 322 covers the opening 3210. The opening 3210 at the end of the housing 321 along its length X direction facilitates the insertion of the electrode assembly 31 into the housing 321. The end cap 322 is then sealed over the opening 3210; for example, the end cap 322 can be glued or welded to the housing 321 to seal the housing 322, thus effectively protecting the electrode assembly 31.

[0189] In some embodiments, please refer to Figure 3 and Figure 4An opening 3210 can be provided at both opposite ends of the housing 321 along its length X. Correspondingly, there are two end caps 322, which are respectively sealed over the two openings 3210. This structure facilitates the processing and manufacturing of the housing 321 and allows for the convenient extension of the tabs 312 from both ends of the main body 311 of the electrode assembly 31.

[0190] In some embodiments, an opening 3210 may be provided at one end of the housing 321 in the length direction X, and correspondingly, an end cap 322 may be provided to cover the opening 3210.

[0191] In some embodiments, please refer to Figure 3 and Figure 4 The battery cell 300 also includes a tray 36, which is installed in the housing 32 to position the electrode assembly 31. The tray 36 allows for better positioning of the electrode assembly 31 and reduces deformation of the electrode assembly 31's edges caused by the rounded corners of the housing 32. The tray 36 can be made of materials such as ceramic, plastic, or silicone.

[0192] In some embodiments, the electrode assembly 31 is provided with a support plate 36 at at least one end along the width direction Z to position the electrode assembly 31.

[0193] In some embodiments, please refer to Figure 3 and Figure 4 When the housing 32 is provided with a pressure relief mechanism 323 on the side wall in the width direction Z, the tray 36 is provided with a groove 361 corresponding to the position of the pressure relief mechanism 323, so that in the event of thermal runaway of the battery cell 300 and generation of gas, the groove 361 on the tray 36 can be broken through and the gas can be discharged, thereby reducing the risk of the tray 36 blocking or blocking the pressure relief mechanism 323.

[0194] In some embodiments of the present application, the present application provides a battery cell 300, including a housing 32 and an electrode assembly 31. The housing 32 has a length direction X, a width direction Z, and a thickness direction Y. The length L of the housing 32 is greater than or equal to the width W of the housing 32, and the width W of the housing 32 is greater than or equal to the thickness T of the housing 32. The electrode assembly 31 is disposed in the housing 32. The electrode assembly 31 is a stacked structure and includes a plurality of electrode tabs 310 stacked along the thickness direction Y. The electrode tab 310 includes a main body portion 311 and a tab 312 provided at an end of the main body portion 311 along the length direction X. The main body portion 311 includes a current collector 3111 and active material layers 3112 provided on both sides of the current collector 3111 along the thickness direction Z. The tab 312 is connected to the current collector 3111. The internal resistance range of the current collector 3111 is 0.97 mΩ - 26.89 mΩ. The current collector 3111 includes a negative current collector 31021. The width of the negative current collector 31021 is W1, the thickness is T1, the length is L1, and the current-carrying area of the negative current collector 31021 is S1 = W1 * T1, and 0.0008 mm < S1 / L1 < 0.001 mm. The thickness T1 of the negative current collector 31021 is greater than or equal to 4.5 μm. The current collector 3111 includes a positive current collector 31011. The width of the positive current collector 31011 is W2, the thickness is T2, the length is L2, and the current-carrying area of the positive current collector 31011 is S2 = W2 * T2, and 0.0017 mm < S2 / L2 < 0.0022 mm. The thickness T2 of the positive current collector 31011 is greater than or equal to 10 μm. The length L range of the housing 32 is 100 mm - 400 mm; the width W range of the housing 32 is 60 mm - 150 mm; the thickness T range of the housing 32 is 20 mm - 80 mm.

[0195] Through the above structural design, the battery cell 300 can have a high volumetric energy density, and can withstand a large current, improving the over-current capacity and charge-discharge performance of the battery cell 300, and achieving high-rate charge and discharge.

[0196] In some embodiments of the present application, the present application further provides a battery device 200, including the battery cell 300 as described in the above embodiments.

[0197] In some embodiments of the present application, the present application further provides an electrical device, including the battery cell 300 as described in the above embodiments or the battery device as described in the above embodiments. The battery cell 300 or the battery device is used to store or provide electrical energy.

[0198] 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 in that, include: An outer casing having a length direction, a width direction, and a thickness direction, wherein the length of the outer casing is greater than or equal to the width of the outer casing, and the width of the outer casing is greater than or equal to the thickness of the outer casing; The electrode assembly has a stacked structure and is disposed within the housing. The electrode assembly includes multiple electrode sheets stacked along the thickness direction. Each electrode sheet includes a main body and tabs disposed at the ends of the main body along the length direction. The main body includes a current collector and active material layers disposed on both sides of the current collector along the thickness direction. The tabs are connected to the current collector. The internal resistance of the current collector is in the range of 0.97mΩ-26.89mΩ. The current collector includes a negative current collector and a positive current collector.

2. The battery cell as described in claim 1, characterized in that, The internal resistance of the negative electrode current collector ranges from 1.12 mΩ to 26.89 mΩ.

3. The battery cell as described in claim 1, characterized in that, The width of the negative electrode current collector is W1, the thickness of the negative electrode current collector is T1, the length of the negative electrode current collector is L1, and the flow area of ​​the negative electrode current collector is S1=W1*T1, S1 / L1>0.0006mm.

4. The battery cell as described in claim 3, characterized in that, 0.0008mm <S1 / L1<0.001mm。 5. The battery cell according to any one of claims 1-4, characterized in that, The thickness of the negative electrode current collector is greater than or equal to 4.5 μm.

6. The battery cell as described in claim 5, characterized in that, The thickness of the negative electrode current collector ranges from 5 μm to 8 μm.

7. The battery cell according to any one of claims 1-4 and 6, characterized in that, The internal resistance of the positive current collector ranges from 0.97 mΩ to 19.57 mΩ.

8. The battery cell according to any one of claims 1-4 and 6, characterized in that, The width of the positive electrode current collector is W2, the thickness of the positive electrode current collector is T2, the length of the positive electrode current collector is L2, and the flow area of ​​the positive electrode current collector is S2=W2*T2, S2 / L2>0.0014mm.

9. The battery cell as described in claim 8, characterized in that, 0.0017mm <S2 / L2<0.0022mm。 10. The battery cell according to any one of claims 1-4, 6, and 9, characterized in that, The thickness of the positive electrode current collector is greater than or equal to 10 μm.

11. The battery cell as described in claim 10, characterized in that, The thickness of the positive electrode current collector ranges from 13μm to 15μm.

12. The battery cell according to any one of claims 1-4, 6, 9, and 11, characterized in that, The length of the outer casing ranges from 100mm to 400mm; and / or the width of the outer casing ranges from 60mm to 150mm; and / or the thickness of the outer casing ranges from 20mm to 80mm.

13. The battery cell as described in claim 12, characterized in that, The difference between the length of the outer shell and the length of the electrode is in the range of 8mm-24mm.

14. The battery cell as described in claim 12, characterized in that, The difference between the width of the outer shell and the width of the electrode is in the range of 1.7mm-3.3mm.

15. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-14.

16. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-14 or a battery device as described in claim 15, wherein the battery cell or the battery device is used to store or provide electrical energy.

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