Battery monomer, battery device and electric equipment

Abstract

The utility model discloses a battery monomer, a battery device and electric equipment. The battery monomer comprises a shell and an electrode assembly, and the electrode assembly is arranged in the shell. The electrode assembly comprises an isolating membrane and a pole piece which are stacked, and the pole piece comprises a main body part and a tab. A thinned area is arranged on the main body part, a porous coating is arranged on the surface, facing the pole piece, of the isolating membrane, and at least part of the porous coating corresponds to the thinned area. According to the technical scheme, the operation stability of the battery monomer can be improved.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a battery cell, a battery device, and an electrical appliance. Background Technology

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

[0003] The development of battery technology must take into account multiple design factors. Improving the stability of a single battery cell during operation is a research direction in the battery field. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device that can improve the operational stability of the battery cell.

[0005] In a first aspect, this application provides a battery cell, including a housing and an electrode assembly. The electrode assembly is disposed within the housing. The electrode assembly includes a separator and an electrode sheet stacked together, the electrode sheet including a main body and a tab. The main body has a thinning region, and the surface of the separator facing the electrode sheet has a porous coating, at least a portion of which corresponds to the thinning region.

[0006] In the technical solution of this application embodiment, a shell is provided to offer a stable environment for the electrode assembly, reducing the impact of external impurities and moisture on the electrode assembly and improving the operational stability of the battery cell. The main body of the electrode is the primary component for the conversion of electrical and chemical energy in the battery cell, and the tabs of the electrode can transmit the electrical energy generated by the main body to the outside. The separator can form insulation between electrodes of different polarities and between the electrode and the shell, improving insulation safety. A porous coating is provided at the location of the separator corresponding to the thinning area. On the one hand, this can compensate for the reduced density between the electrodes caused by the thickness difference in the thinning area; on the other hand, the porous layer can store part of the electrolyte, improving the electrolyte wetting performance of the thinning area, reducing the risk of heat accumulation and lithium plating in the thinning area, and further improving the operational stability and efficiency of the battery cell.

[0007] In some embodiments, the porous coating includes at least one of a carbon black material layer, a graphite layer, an alumina layer, a polyacrylamide layer, and a lignin layer. The above-described coating structures all possess characteristics of high porosity, corrosion resistance, and high temperature resistance, enabling them to store electrolyte and replenish the thickness of the thinned area, forming a stable porous structure layer.

[0008] In some embodiments, the main body includes a substrate, a first coating, and a second coating. The substrate is connected to one side of the electrode tab along a first direction. The first coating is applied to at least one surface of the substrate. The second coating is applied to at least one surface of the substrate and is connected to the first coating. The maximum thickness of the second coating is less than the minimum thickness of the first coating, and the second coating is disposed on one side of the first coating along the first direction. In the above structure, disposing the second coating at the edge of the substrate along the first direction increases the surface area of ​​the electrode, thereby improving electrode activity and increasing the rate and efficiency of electrochemical reactions. Thinning the sides of the electrode shortens the electron transport path within the electrode, increases the electron transport rate, and thus improves the electrode performance.

[0009] In some embodiments, the substrate has a first edge extending along a second direction perpendicular to the first direction, and a second coating is disposed on the surface of the main body near the first edge and adjacent to the tab. This structure, by placing the thinned region near the tab, helps to distribute the current more evenly on the electrode sheet, reducing uneven current distribution on the electrode sheet, thereby improving the performance and stability of the battery cell. The thinned region can reduce the resistance of the electrode sheet near the tab, thereby reducing the internal resistance of the battery cell and improving its power output capability.

[0010] In some embodiments, along a first direction, the separator extends beyond the first edge of the substrate to form an extension, a first portion of the porous coating covers the extension, and a second portion of the porous coating is provided corresponding to the second coating portion. In the above structure, by providing the extension, the edge of the electrode is covered, increasing the creepage distance between the electrode and the housing, as well as between adjacent electrodes, thereby improving insulation performance.

[0011] In some embodiments, the second portion of the porous coating has a second edge extending along a second direction, the second edge being located on the side of the second portion away from the first portion, a first boundary being formed between the first coating and the second coating, and the second edge being spaced apart from the first boundary. In the above structure, the porous coating covers the extension portion, and a second coating is provided for the corresponding portion. The second coating is not provided near the first coating, which reduces the risk of excessive thickness caused by uneven thickness of the second coating and improves the overall flatness of the electrode assembly.

[0012] In some embodiments, along the first direction, the extension dimension is H1, the second coating dimension is H2, and the porous coating dimension is H3. H1, H2, and H3 satisfy the relationship: 1mm ≤ (H1 + H2) - H3 ≤ 4mm. In the above structure, the porous coating is not provided in the region of the second coating close to the first coating, which can improve the overall flatness of the electrode assembly.

[0013] In some embodiments, along the first direction, the size H2 of the second coating is: 2mm ≤ D ≤ 10mm; the size H3 of the porous coating is: 2mm ≤ H3 ≤ 10mm. By setting appropriate widths for the second coating and the porous coating, the overall flatness of the electrode assembly can be improved, thereby increasing the compaction density between the electrode sheet and the separator.

[0014] In some embodiments, along the thickness direction of the battery cell, which is perpendicular to both the first and second directions, the maximum size of the first coating is T1, the minimum size of the second coating is T2, and the maximum size of the porous coating is T3. T1, T2, and T3 satisfy the following relationships: 2mm ≤ T1 - T2 ≤ 4mm, 1mm ≤ T3 ≤ 3mm. In the above structure, by setting a reasonable thinning area and the thickness of the porous coating, the flatness of the electrode assembly can be improved, while reducing the risk of lithium plating and heat accumulation in the second coating area. Furthermore, the porous coating can store an appropriate amount of electrolyte, improving the electrolyte wetting performance of the second coating.

[0015] In some embodiments, the cross-sectional area of ​​the second coating gradually decreases along the direction from the main body towards the tab. The above structure effectively increases the surface area of ​​the second coating region, enhances the activity of the electrode, and is easy to manufacture with high production efficiency.

[0016] In some embodiments, the cross-sectional area of ​​the porous coating gradually increases along the direction from the main body towards the tab. This structure, corresponding to the shape of the thinned region, can improve the flatness and density of the electrode assembly.

[0017] Secondly, this application provides a battery device that includes the battery cell described in the above embodiments.

[0018] Thirdly, this application provides an electrical device that includes the battery described in the above embodiments, the battery being used to provide electrical energy.

[0019] 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, the following are specific embodiments of this application. Attached Figure Description

[0020] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0021] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0022] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0023] Figure 2 Explosion-proof diagrams of battery devices provided in some embodiments of this application;

[0024] Figure 3 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0025] Figure 4 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0026] Figure 5 Exploded view of electrode assemblies provided in some embodiments of this application;

[0027] Figure 6 This is a schematic diagram of the structure of the electrode provided in some embodiments of this application;

[0028] Figure 7 A partial structural schematic diagram of an electrode assembly provided in some embodiments of this application;

[0029] Figure 8 A partial structural schematic diagram of an electrode assembly provided for other embodiments of this application;

[0030] Figure 9 This is a partial structural schematic diagram of an electrode assembly provided in some embodiments of this application.

[0031] Detailed Explanation of Reference Numerals

[0032] 1. Vehicle; 2. Battery assembly; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Reception space; 6. Battery cell; 10. Electrode assembly; 101. Separator; 102. Electrode sheet; 103. Porous coating; 104. Substrate; 105. First coating; 106. Second coating; 107. First edge; 108. Extension; 109. First part; 110. Second part; 111. Second edge; 112. First boundary; 20. Housing; 25. Electrode terminal; 30. End cap; 40. Outer shell; X, First direction; Y, Second direction; Z, Thickness direction. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] 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.

[0035] 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. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0036] 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.

[0037] 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.

[0038] 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).

[0039] 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," and "circumferential" 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 are not intended to 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.

[0040] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0041] 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.

[0042] 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.

[0043] 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. For example, if the angle between two directions is 85°-95°, the two directions can be considered perpendicular; if the angle between two directions is 0°-5°, the two directions can be considered parallel.

[0044] In this application, "multiple" means two or more (including two).

[0045] 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.

[0046] 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.

[0047] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0048] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0049] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0050] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0051] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0052] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0053] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0054] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0055] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0056] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0057] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0058] Liquid electrolytes include electrolyte salts and solvents.

[0059] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0060] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0061] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0062] In some implementations, the electrode assembly is a stacked structure.

[0063] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0064] 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.

[0065] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0066] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0067] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0068] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0069] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0070] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0071] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0072] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0073] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0074] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0075] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0076] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0077] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0078] 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.

[0079] 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.

[0080] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0081] Electrode components include positive electrode, negative electrode, separator, and electrolyte. During electrode manufacturing, due to the fluidity and surface tension of the slurry, it tends to accumulate at the edges, causing a sudden increase in coating thickness and forming a crescent-shaped feature. To address this issue, current manufacturing processes often employ edge thinning to reduce slurry accumulation at the edges. However, with electrode thicknesses only a few hundred micrometers, precisely controlling the distribution of micron-level non-Newtonian fluids is challenging. This can easily lead to excessive thinning of the thinned area during manufacturing, resulting in lithium plating in the thinned region and affecting the electrical performance and safety of the battery cell.

[0082] In view of this, this application provides a battery cell with a casing to provide a stable environment for the electrode assembly, reducing the impact of external impurities and moisture on the electrode assembly and improving the operational stability of the battery cell. The main body of the electrode is the main component for the conversion of electrical and chemical energy in the battery cell, and the tabs of the electrode can transmit the electrical energy generated by the main body to the outside. The separator can form insulation between electrodes of different polarities and between the electrode and the casing, improving insulation safety. A porous coating is provided at the location of the separator corresponding to the thinning area. On the one hand, it can compensate for the reduced density between the electrodes caused by the excessive thinning area. On the other hand, the porous layer can store part of the electrolyte, improve the electrolyte wetting performance of the thinned area, reduce the risk of heat accumulation and lithium plating in the thinned area, and further improve the operational stability and efficiency of the battery cell.

[0083] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0084] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0085] like Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can 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.

[0086] 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.

[0087] 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.

[0088] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and battery cells 6, with the battery cells 6 housed within the housing 5. The battery cell 6 can be the smallest unit that makes up a battery.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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 manner. A mixed connection means that multiple battery cells 6 are connected in both series and parallel.

[0093] Multiple battery cells 6 can be directly connected in series, parallel, or in a mixed manner, and then the whole composed of multiple battery cells 6 can be housed in the housing 5; of course, multiple battery cells 6 can also be connected in series, parallel, or in a mixed manner to form a battery module, and multiple battery modules can then be connected in series, parallel, or in a mixed manner to form a whole, and housed in the housing 5.

[0094] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application.

[0095] like Figure 3 As shown, in some embodiments, the battery cell 6 includes a housing 40 and an electrode assembly 10 housed within the housing 40.

[0096] 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.

[0097] The housing 40 is used to encapsulate the electrode assembly 10 and electrolyte components. The housing 40 can be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite housing 40), or aluminum-plastic film, etc.

[0098] In some embodiments, the housing 40 includes a housing 20 and an end cap 30, the housing 20 having an opening and the end cap 30 for closing the opening.

[0099] In some embodiments, the battery cell 6 further includes an electrolyte housed within the casing 40. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid.

[0100] In some embodiments, the battery cell 6 includes electrode terminals 25. The electrode terminals 25 are electrically connected to the electrode assembly 10 for outputting or inputting electrical energy into the battery cell 6.

[0101] Please refer to the reference. Figures 3 to 5 , Figure 3 This is an exploded schematic diagram of a battery cell provided in some embodiments of this application. Figure 4 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application. Figure 5 This is an exploded view of an electrode assembly provided in some embodiments of this application.

[0102] As shown in the figure, the battery cell 6 provided in this embodiment includes a housing 40 and an electrode assembly 10. The electrode assembly 10 is disposed within the housing 40. The electrode assembly 10 includes a separator 101 and an electrode 102 stacked together. The electrode 102 includes a main body and an electrode tab. A thinning area is provided on the main body, and a porous coating 103 is provided on the surface of the separator 101 facing the electrode 102. At least a portion of the porous coating 103 is disposed corresponding to the thinning area.

[0103] For example, the electrode 102 includes a cathode electrode 102 and an anode electrode 102, which are respectively disposed on opposite sides of the separator 101. The cathode electrode 102 and the anode electrode 102 are respectively provided with thinning areas, and the separator 101 is respectively provided with porous coatings 103 on both sides.

[0104] The separator 101 is located between electrodes 102 of different polarities and between the electrodes 102 and the casing 40, serving as insulation to prevent short circuits and improve battery safety. The electrodes 102 include a main body and tabs. The main body is the primary area for the conversion of electrical and chemical energy in the battery; the tabs are used to transmit the electrical energy generated in the main body to the external circuitry.

[0105] A thinning region is provided on the main body of the electrode 102. This design aims to reduce weight, optimize battery structure, or increase energy density. It also increases the specific surface area of ​​the active material layer, thereby improving the operating efficiency of the battery cell 6.

[0106] A porous coating 103 is provided at the position corresponding to the thinned area of ​​the separator 101. A porous material layer of a certain thickness can be coated on the edge of the separator 101 by means of a micro-gravure, and then dried to form the final product. This method is convenient and efficient in production.

[0107] In the technical solution of this application embodiment, a shell 40 is provided to provide a stable environment for the electrode assembly 10, reducing the impact of external impurities and moisture on the electrode assembly 10 and improving the operational stability of the battery cell 6. The main body of the electrode 102 is the main component for the conversion of electrical energy and chemical energy in the battery cell 6, and the tabs of the electrode 102 can transmit the electrical energy generated by the main body to the outside. The separator 101 can form insulation between electrodes 102 of different polarities and between the electrode 102 and the shell 40, improving insulation safety. A porous coating 103 is provided at the position of the separator 101 corresponding to the thinning area. On the one hand, it can compensate for the reduced density between the electrodes 102 caused by the thickness difference in the thinning area. On the other hand, the porous layer can store part of the electrolyte, improve the electrolyte wetting performance of the thinning area, reduce the risk of heat accumulation and lithium plating in the thinning area, and further improve the operational stability and efficiency of the battery cell 6.

[0108] In some embodiments of this application, the porous coating 103 includes at least one of a carbon black material layer, a graphite layer, an alumina layer, a polyacrylamide layer, and a lignin layer. Exemplarily, the porous coating 103 can be formed by mixing a porous material with a binder to form a coating slurry, then applying the slurry to the corresponding area, and drying it to form the porous coating 103. The binder can be polyvinylidene fluoride (PVDF), or a polymer containing nitrogen, oxygen, and fluorine polar elements such as polyacrylic acid and its salts, sodium alginate, and polyvinyl alcohol. The porous material can be any one or a mixture of any of the following: carbon black, alumina, polyacrylamide, graphite, and lignin.

[0109] Carbon black is a highly porous carbon material with excellent electrical conductivity and electrochemical activity. In the porous coating 103, carbon black can provide good electron transport channels, while its porous structure facilitates electrolyte storage and permeation.

[0110] Graphite is a layered carbon material with good electrical conductivity and thermal stability. In the porous coating 103, graphite can provide a stable conductive network, while its layered structure facilitates the diffusion and storage of the electrolyte.

[0111] Alumina is a ceramic material with high hardness, high corrosion resistance, and high thermal stability. In porous coating 103, alumina can provide good mechanical support and chemical stability, helping to protect the substrate from corrosion and high temperatures.

[0112] Polyacrylamide is an organic polymer material with good water absorption and retention capabilities. In the porous coating 103, polyacrylamide can serve as a storage medium for the electrolyte, while its porous structure facilitates the uniform distribution and penetration of the electrolyte.

[0113] Lignin is a natural organic polymer material derived from plant cell walls. Lignin layers possess a porous structure and a certain degree of electrical conductivity, while also exhibiting good biocompatibility and environmental friendliness. In the porous coating 103, lignin can provide additional electrolyte storage space and contribute to improving the coating's biocompatibility and environmental adaptability.

[0114] The above-mentioned coating structures all have the characteristics of being porous, corrosion-resistant, and high-temperature resistant. They can store electrolyte and replenish the thickness of the thinned area to form a stable porous structure layer.

[0115] like Figure 6As shown, in some embodiments of this application, the main body includes a substrate 104, a first coating 105, and a second coating 106. The substrate 104 is connected to one side of the electrode tab along a first direction X. The first coating 105 is coated on at least one surface of the substrate 104. The second coating 106 is coated on at least one surface of the substrate 104 and is connected to the first coating 105. The maximum thickness of the second coating 106 is less than the minimum thickness of the first coating 105, and the second coating 106 is disposed on one side of the first coating 105 along the first direction X.

[0116] The second coating 106 is located at the edge of the substrate 104, increasing the overall surface area of ​​the electrode 102. A larger surface area provides more reaction sites, thereby improving electrode activity. The second coating 106 can also act as a buffer for current distribution, contributing to a more uniform current distribution on the electrode 102 and shortening the electron transport path.

[0117] Optionally, if the second coating 106 is thinned on both sides of the electrode 102 along the first direction X, the electron transport path inside the electrode 102 is further shortened, which helps to improve the electron transport rate and thus improve the performance of the electrode.

[0118] In the above structure, placing the second coating 106 on the edge of the substrate 104 along the first direction X increases the surface area of ​​the electrode 102, thereby improving electrode activity and increasing the rate and efficiency of the electrochemical reaction. Thinning both sides of the electrode 102 shortens the electron transport path within the electrode 102, increasing the electron transport rate and thus improving electrode performance.

[0119] In some embodiments of this application, the substrate 104 has a first edge 107 extending along a second direction Y, the second direction Y being perpendicular to the first direction X, and a second coating 106 is disposed on the surface of the main body near the first edge 107 and adjacent to the tab.

[0120] For example, the first direction X can be the height direction of the battery cell 6, and the second direction Y can be the width direction of the battery cell 6. The second coating 106 is close to the tab, and the porous coating 103 on the separator 101 corresponds to the second coating 106, which can improve the electrolyte wettability at this location and reduce the risk of lithium plating in this area.

[0121] The aforementioned structure, by placing the thinned region near the tab, helps to distribute the current more evenly on the electrode sheet 102, reducing uneven current distribution on the electrode sheet 102, thereby improving the performance and stability of the battery cell 6. The thinned region can reduce the resistance of the electrode sheet 102 near the tab, thereby reducing the internal resistance of the battery cell 6 and improving the power output capability of the battery cell 6.

[0122] like Figure 7As shown, in some embodiments of this application, along the first direction X, the isolation membrane 101 extends beyond the first edge 107 of the substrate 104 to form an extension 108, the first portion 109 of the porous coating 103 covers the extension 108, and the second portion 110 of the porous coating 103 corresponds to the portion of the second coating 106.

[0123] Creepage distance refers to the path length required for current to pass through the surface of an insulating material instead of directly through it. Increasing the creepage distance reduces the risk of current leakage at the surface of the insulating material, thereby improving the insulation performance of the battery.

[0124] The first portion 109 of the porous coating 103 covers the extension 108, thereby enhancing the structural strength of that area. The second portion 110 of the porous coating 103 is provided with a corresponding second coating 106, thereby improving the electrolyte wetting performance of that area.

[0125] In the above structure, by providing the extension 108 to cover the edge of the electrode 102, the creepage distance between the electrode 102 and the outer casing 40 and between adjacent electrode 102 is increased, thereby improving the insulation performance.

[0126] In some embodiments of this application, the second portion 110 of the porous coating 103 has a second edge 111 extending along the second direction Y. The second edge 111 is located on the side of the second portion 110 away from the first portion 109. A first boundary 112 is between the first coating 105 and the second coating 106. The second edge 111 and the first boundary 112 are spaced apart.

[0127] The second edge 111 and the first boundary 112 are spaced apart, and there is a certain spatial separation between the porous coating 103 and the first coating 105, that is, the porous coating 103 is not provided in a part of the isolation film 101 corresponding to the second coating 106.

[0128] The porous coating 103 covers the extension 108, but the second coating 106 is not provided with the porous coating 103 near the first coating 105. This can effectively reduce the decrease in the compaction density of the electrode 102 caused by the reduction in the thickness of the second coating 106.

[0129] Meanwhile, by not placing the porous coating 103 near the first coating 105 in the second coating 106, the risk of excessive overall thickness due to uneven thickness of the second coating 106 can be reduced. This is because the porous coating 103 itself may increase the thickness, and if applied uncontrollably, it may cause the electrode assembly 10 to be too thick in certain areas, affecting the overall flatness.

[0130] In the above structure, the porous coating 103 covers the extension 108, and the corresponding part is provided with a second coating 106. The second coating 106 is not provided with a porous coating 103 near the first coating 105, which can reduce the risk of excessive thickness caused by uneven thickness of the second coating 106 and improve the overall flatness of the electrode assembly 10.

[0131] like Figure 8 As shown, in some embodiments of this application, along the first direction X, the extension 108 has a size of H1, the second coating 106 has a size of H2, and the porous coating 103 has a size of H3. H1, H2, and H3 satisfy the relationship: 1mm≤(H1+H2)-H3≤4mm.

[0132] By adjusting these dimensions, the thickness distribution of the electrode assembly 10 can be precisely controlled, especially in the region where the second coating 106 meets the porous coating 103. The porous coating 103 is not present in the region of the second coating 106 near the first coating 105, thus avoiding any increase in thickness in this area due to its presence. This design helps reduce the thickness non-uniformity of the electrode assembly 10, thereby improving the overall flatness.

[0133] If the value of (H1+H2)-H3 is too small, the porous coating 103 may not be able to fully cover the edges of the extension 108 and the second coating 106, affecting the insulation performance. If the value of (H1+H2)-H3 is too large, the porous coating 103 may over-cover, causing the electrode assembly 10 to be too thick in some areas, which is not conducive to the optimization of flatness and performance.

[0134] For example, the width H1 of the extension 108 is 3 mm, and the width H2 of the second coating 106 is 10 mm. In this case, the thickness of the porous coating 103 can be set to 10 mm. Specifically, 3 mm is provided in the extension 108, and 7 mm corresponds to a portion of the second coating 106. The second coating 106 also has a 3 mm margin, corresponding to the absence of the porous coating 103. This design helps reduce the risk of excessive thickness in the thinned area of ​​the electrode assembly 10, thereby improving overall flatness. It is understood that a slightly smaller thickness is more conducive to the compaction between the electrode sheets 102 than an excessively large thickness, reducing the risk of delamination between the electrode sheets 102.

[0135] In the above structure, the porous coating 103 is not provided in the area of ​​the second coating 106 near the first coating 105, which can improve the overall flatness of the electrode assembly 10, thereby improving the structural performance and operational stability of the electrode assembly 10.

[0136] In some embodiments of this application, along the first direction X, the dimension H2 of the second coating 106 is: 2mm ≤ D ≤ 10mm; the dimension H3 of the porous coating 103 is: 2mm ≤ H3 ≤ 10mm. For example, the width H2 of the second coating 106 is 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm. The width H3 of the porous coating 103 is 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0137] The specific relationship between the extension 108 dimension H1, the second coating 106 dimension H2, and the porous coating 103 dimension H3 improves the dimensional control accuracy of the electrode assembly 10 along the first direction X.

[0138] By setting appropriate widths for the second coating 106 and the porous coating 103, the overall flatness of the electrode assembly 10 can be improved, thereby increasing the compaction density between the electrode sheet 102 and the separator 101.

[0139] like Figure 9 As shown, in some embodiments of this application, along the thickness direction Z of the battery cell 6, the thickness direction Z is perpendicular to the first direction X and the second direction Y, respectively. The maximum size of the first coating 105 is T1, the minimum size of the second coating 106 is T2, and the maximum size of the porous coating 103 is T3. T1, T2 and T3 satisfy the following relationship: 2mm≤T1-T2≤4mm, 1mm≤T3≤3mm.

[0140] The thickness difference (T1-T2) between the first coating 105 and the second coating 106 satisfies the relationship 2mm ≤ T1-T2 ≤ 4mm. This design helps to form a thinning zone of reasonable thickness in the electrode assembly 10. The presence of the thinning zone can balance the non-uniformity of the electrode assembly 10 in the thickness direction Z, thereby improving the overall flatness. By setting a reasonable thinning zone, the current distribution can be optimized and the risk of lithium plating can be reduced.

[0141] The size T3 of the porous coating 103 satisfies the relationship 1mm ≤ T3 ≤ 3mm, allowing the porous coating 103 to store an appropriate amount of electrolyte. The stored electrolyte can be rapidly wetted into the second coating 106 through the porous structure, improving the electrolyte wetting performance. Good wetting performance helps improve the electrochemical performance of the battery, such as increasing energy density and power output. In addition to improving the electrolyte wetting performance, the porous coating 103 can also act as a protective layer, reducing direct contact between the electrode material and the electrolyte, thereby reducing the occurrence of side reactions. The porous coating 103 can also act as a buffer, reducing the volume change of the battery during charge and discharge, further improving the cycle stability of the battery.

[0142] In the above structure, by setting a reasonable thinning area and the thickness of the porous coating 103, the flatness of the electrode assembly 10 can be improved, while reducing the risk of lithium plating and heat accumulation in the second coating 106 area. Furthermore, the porous coating 103 can store an appropriate amount of electrolyte, thereby improving the wetting performance of the electrolyte in the second coating 106.

[0143] In some embodiments of this application, the cross-sectional area of ​​the second coating 106 gradually decreases along the direction from the main body toward the tab.

[0144] This gradually decreasing cross-sectional area design can be achieved through simple manufacturing processes, such as layer-by-layer coating or laser cutting. Compared to complex structures, this design is easier to automate, thereby improving production efficiency. Efficient manufacturing processes help reduce production costs.

[0145] Meanwhile, the gradual reduction in the cross-sectional area of ​​the second coating 106 also reduces the volume change of the electrode material during charging and discharging to some extent, thereby improving the battery's durability. Furthermore, this design helps optimize the current distribution inside the battery, reduces internal resistance, and improves the battery's energy conversion efficiency.

[0146] The above structure can effectively increase the surface area of ​​the second coating region 106, improve the activity of the electrode, and is easy to manufacture with high production efficiency.

[0147] In some embodiments of this application, the cross-sectional area of ​​the porous coating 103 gradually increases along the direction from the main body toward the tab.

[0148] As the cross-sectional area of ​​the porous coating 103 gradually increases along the direction from the main body towards the tab, it can better match the thickness changes caused by the thinning zone. This matching design ensures that the porous coating 103 can effectively promote electrolyte wetting and storage while compensating for the thickness changes in the thinning zone.

[0149] The above-described structure, corresponding to the shape of the thinning area, can improve the flatness and density of the electrode assembly 10.

[0150] In some alternative embodiments, the battery cell 6 includes a housing 40 and an electrode assembly 10. The electrode assembly 10 is disposed within the housing 40. The electrode assembly 10 includes a separator 101 and an electrode sheet 102 stacked together. The electrode sheet 102 includes a main body and a tab. A thinning area is provided on the main body, and a porous coating 103 is provided on the separator 101, with the porous coating 103 corresponding to the thinning area. The porous coating 103 includes a carbon graphite layer. The main body includes a substrate 104, a first coating 105, and a second coating 106. The substrate 104 is connected to one side of the tab along a first direction X. The first coating 105 is coated on at least one surface of the substrate 104. The second coating 106 is coated on at least one surface of the substrate 104 and is connected to the first coating 105. The maximum thickness of the second coating 106 is less than the minimum thickness of the first coating 105, and the second coating 106 is disposed on one side of the first coating 105 along the first direction X. Along the first direction X, the separator 101 extends beyond the first edge 107 of the substrate 104 to form an extension 108. A first portion 109 of the porous coating 103 covers the extension 108, and a second portion 110 of the porous coating 103 corresponds to a second coating 106. The second portion 110 of the porous coating 103 has a second edge 111 extending along the second direction Y. The second edge 111 is located on the side of the second portion 110 away from the first portion 109. A first boundary 112 is formed between the first coating 105 and the second coating 106, and the second edge 111 and the first boundary 112 are spaced apart. Along the direction from the main body towards the tab, the cross-sectional area of ​​the second coating 106 gradually decreases. Along the direction from the main body towards the tab, the cross-sectional area of ​​the porous coating 103 gradually increases.

[0151] This application provides a battery device 2, which includes the battery cell 6 described in the above embodiments. This application also provides an electrical device, which includes the battery described in the above embodiments, the battery being used to provide electrical energy. It is provided with a housing 40 to provide a stable environment for the electrode assembly 10, reducing the impact of external impurities and moisture on the electrode assembly 10, and improving the operational stability of the battery cell 6. The main body of the electrode 102 is the main component for the conversion of electrical and chemical energy in the battery cell 6, and the tabs of the electrode 102 can transmit the electrical energy generated by the main body to the outside. The separator 101 can form insulation between electrodes 102 of different polarities, and between the electrode 102 and the housing 40, improving insulation safety. A porous coating 103 is provided at the location of the separator 101 corresponding to the thinned area. On the one hand, this can compensate for the reduced density between the electrodes 102 caused by an excessively large thinned area; on the other hand, the porous layer can store part of the electrolyte, improving the electrolyte wetting performance of the thinned area, reducing the risk of heat accumulation and lithium plating in the thinned area, further improving the operational stability and efficiency of the battery cell 6.

[0152] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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; an electrode assembly disposed in the housing, the electrode assembly comprising a separator and a tab, the tab comprising a main body and a tab ear, the main body being provided with a thinned region, the separator being provided with a porous coating on a surface facing the tab, at least a portion of the porous coating corresponding to the thinned region.

2. The battery cell of claim 1, wherein, The porous coating comprises at least one of a carbon black material layer, a graphite layer, an aluminum oxide layer, a polyacrylamide layer, and a lignin layer.

3. The battery cell of claim 2, wherein, The main body comprises: a base connected to one side of the tab ear along a first direction; a first coating applied to at least one surface of the base; a second coating applied to at least one surface of the base and connected to the first coating, the second coating having a maximum thickness smaller than a minimum thickness of the first coating, the second coating being disposed on one side of the first coating along the first direction.

4. The battery cell of claim 3, wherein, The base has a first edge extending along a second direction perpendicular to the first direction, the second coating being disposed on a surface of the main body close to the first edge and abutting the tab ear.

5. The battery cell of claim 4, wherein, Along the first direction, the separator extends beyond the first edge of the base to form an extension, a first portion of the porous coating covering the extension, and a second portion of the porous coating corresponding to the second coating.

6. The battery cell of claim 5, wherein, The second portion of the porous coating has a second edge extending along the second direction, the second edge being disposed on a side of the second portion away from the first portion, the first coating and the second coating having a first boundary therebetween, and the second edge being spaced apart from the first boundary.

7. The battery cell of claim 6, wherein, Along the first direction, the extension has a size H1, the second coating has a size H2, and the porous coating has a size H3, H1, H2, and H3 satisfying the relationship: 1 mm ≤ (H1 + H2) - H3 ≤ 4 mm.

8. The battery cell of any one of claims 4-7, wherein, Along the first direction, the size H2 of the second coating satisfies: 2 mm ≤ D ≤ 10 mm, and the size H3 of the porous coating satisfies: 2 mm ≤ H3 ≤ 10 mm.

9. The battery cell of any one of claims 4-7, wherein, Along a thickness direction of the battery cell, the thickness direction being perpendicular to the first direction and the second direction, a maximum size of the first coating is T1, a minimum size of the second coating is T2, and a maximum size of the porous coating is T3, T1, T2, and T3 satisfying the relationship: 2 mm ≤ T1 - T2 ≤ 4 mm, and 1 mm ≤ T3 ≤ 3 mm.

10. The battery cell of any one of claims 3-7, wherein, Along a direction of the main body towards the tab ear, the cross-sectional area of the second coating gradually decreases.

11. The battery cell of claim 10, wherein, Along a direction of the main body towards the tab ear, the cross-sectional area of the porous coating gradually increases.

12. A battery device characterized by comprising: The battery device comprises the battery cell according to any one of claims 1-11.

13. An electrical device, characterized by The electrical equipment comprises the battery device according to claim 12, the battery device being configured to provide electrical energy.

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