Battery monomer, battery device and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device, the battery monomer comprises a shell, an electrode assembly, an electrode terminal, electrolyte and an insulating part, the shell comprises a wall part, the electrode assembly is arranged in the shell, and the electrode assembly comprises an electrode main body and a tab led out from the electrode main body. The electrode terminal is arranged on the wall part and is electrically connected to the tab; and the electrolyte is accommodated in the shell. The insulating part is arranged between the wall part and the electrode main body, the insulating part comprises an insulating body and a protective coating arranged on the surface of the insulating body, the protective coating is at least partially arranged on the side, facing the electrode main body, of the insulating body, and the electrolyte swelling degree of the protective coating is smaller than that of the insulating body. In the embodiment of the invention, the existence of the protective coating can prevent the contact between the surface, facing one side of the electrode main body, of the insulating body and the electrolyte, so that an effective blocking effect on the electrolyte is achieved, and the expansion degree of the insulating body is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Art

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells has become a research direction in battery technology. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery device and an electrical device, which can improve the reliability of the battery cell.

[0005] In one aspect, embodiments of the present application provide a battery cell comprising a housing, an electrode assembly, electrode terminals, an electrolyte, and an insulating member. The housing comprises a wall portion, the electrode assembly is disposed within the housing, and the electrode assembly comprises an electrode body and a tab extending from the electrode body. The electrode terminal is disposed within the wall portion and electrically connected to the tab, and the electrolyte is contained within the housing.

[0006] The insulating member is arranged between the wall and the electrode body, and the insulating member includes an insulating body and a protective coating arranged on the surface of the insulating body. The protective coating is at least partially arranged on the side of the insulating body facing the electrode body, and the electrolyte swelling degree of the protective coating is less than the electrolyte swelling degree of the insulating body.

[0007] In the above solution, a protective coating is added to the insulating element. This coating has a low electrolyte swelling ratio, so even if it comes into contact with the electrolyte, it will not expand excessively. Furthermore, the protective coating is at least partially located on the side of the insulating element facing the electrode body. Therefore, the presence of the protective coating can also hinder contact between the surface of the insulating element facing the electrode body and the electrolyte, effectively blocking the electrolyte and reducing the expansion of the insulating element. This reduces the degree of compression of the electrode assembly by the insulating element without adding or changing the internal mechanical structure of the battery cell, thereby improving the reliability of the battery cell.

[0008] In some embodiments, the electrolyte swelling degree of the protective coating is a, and a satisfies a≤0.1%.

[0009] In the above scheme, by adjusting the material composition of the protective coating, the electrolyte swelling degree a of the protective coating is not greater than 0.1%. This can not only reduce the expansion degree of the protective coating, but also improve the barrier effect of the protective coating on the electrolyte, thereby hindering the contact between the insulating body and the electrolyte, reducing the expansion degree of the insulating body, reducing the degree of extrusion of the insulating part on the electrode assembly, and improving the reliability of the battery cell.

[0010] In some embodiments, the protective coating comprises an organic material.

[0011] In the above solution, at least some organic materials have low surface energy, that is, low surface tension, which makes it difficult for solvent molecules to adhere to their surface, thereby effectively preventing solvent penetration. Given this, the embodiments of the present application provide a protective coating comprising an organic material, thereby imparting low surface energy to the protective coating. This reduces electrolyte penetration, reduces expansion of the protective coating, and minimizes contact between the electrolyte and the insulating body, thereby reducing the overall expansion of the insulating member and improving the reliability of the battery cell.

[0012] In some embodiments, the organic material is polytetrafluoroethylene, polyether ether ketone, polyphenylene sulfide, liquid crystal polymer, polyimide, or fluororubber.

[0013] In the above scheme, polytetrafluoroethylene, polyether ketone, polyphenylene sulfide, liquid crystal polymer, polyimide, and fluororubber are all low-surface-energy materials. For example, the protective coating material includes polytetrafluoroethylene. Polytetrafluoroethylene has a compact molecular structure and extremely low surface energy, making it difficult for electrolyte to penetrate. Specifically, the core component of polytetrafluoroethylene is a thin film with pores much smaller than the diameter of liquid droplets. Therefore, it is difficult for electrolyte to penetrate the protective coating. Even if the protective coating comes into contact with the electrolyte, the electrolyte will not cause the protective coating to expand excessively. At the same time, the protective coating can prevent the electrolyte from reaching the insulating body, thereby reducing the overall expansion of the insulating component.

[0014] In some embodiments, the first protrusion surrounds the second protrusion; or, the second protrusion surrounds the first protrusion.

[0015] In the above scheme, by arranging the first protrusion around the second protrusion, or arranging the second protrusion around the first protrusion, the orthographic projection of the first welding portion and the orthographic projection of the second welding portion can be offset from each other in the same projection plane perpendicular to the thickness direction. This helps to reduce the risk of excessive thickness of the electrode terminal caused by the first welding portion and the second welding portion being concentrated in the same area of ​​the electrode terminal, thereby reducing the overall size of the battery cell in the thickness direction and improving the energy density of the battery cell.

[0016] In some embodiments, in a thickness direction of the wall portion, at least a portion of the protective coating is located between the insulating body and the tab.

[0017] In the above solution, at least a portion of the protective coating is provided on the side of the insulating body facing the electrode body. The protective coating can correspond to the position of the tab and be sandwiched between the insulating body and the tab. In this design, the presence of the protective coating can reduce the degree of expansion of the portion of the insulating body corresponding to the tab, thereby reducing the pressure of the insulating member on the tab, reducing the risk of the tab sinking and being inserted into the electrode body, and improving the reliability of the battery cell.

[0018] In some embodiments, the battery cell further includes a current collecting member connected between the electrode terminal and the tab. In a thickness direction of the wall portion, at least a portion of the protective coating is located between the insulating body and the current collecting member.

[0019] In the above solution, at least a portion of the protective coating is positioned to correspond to the current collecting member, sandwiched between the insulating body and the current collecting member. This design reduces the expansion of the portion of the insulating body that faces the current collecting member, thereby reducing the compression of the current collecting member by the insulating member, thereby reducing the effect of the tab sinking and improving the reliability of the battery cell.

[0020] In some embodiments, the insulating body extends through the wall portion in a thickness direction to form a through-hole structure, and the through-hole structure is disposed corresponding to the electrode terminal. At least a portion of the protective coating is disposed around the periphery of the through-hole structure; and / or the protective coating is partially disposed on the sidewall of the through-hole structure.

[0021] In the above scheme, the position of the protective coating is further limited, and at least a portion of the protective coating is arranged around the circumference of the through-hole structure, or the protective coating is partially arranged on the side wall of the through-hole structure, so that at least a portion of the structure in the protective coating can be located near the area corresponding to the electrode terminal, thereby hindering the contact between the insulating body and the electrolyte in the area near the electrode terminal, thereby reducing the degree of expansion and deformation of the insulating part in the area near the electrode terminal and improving the structural reliability of the insulating part.

[0022] In some embodiments, the wall portion is penetrated along its thickness to form an injection hole, and the insulating body is penetrated along the thickness of the wall portion to form an injection channel. In the same projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the injection channel is at least partially located outside the orthographic projection of the protective coating.

[0023] In the above scheme, the protective coating does not cover the injection channel. In the same projection plane perpendicular to the thickness direction of the wall, the orthographic projection of the injection channel is at least partially located outside the orthographic projection of the protective coating. Under this design, the protective coating will not completely block the injection channel. In this way, during the injection process, the protective coating will not excessively hinder the flow of electrolyte, thereby reducing the risk of long-term accumulation of electrolyte at the insulating body during the injection process, reducing the risk of excessive expansion of the insulating part during the injection process, and improving the preparation yield of the battery cell.

[0024] In some embodiments, the insulating body includes a first sub-section and a second sub-section that are integrally connected. The second sub-section protrudes from the first sub-section on a side facing the electrode body, and the projection of the second sub-section in the thickness direction of the wall is located outside the projection of the electrode tab. The protective coating is at least partially disposed on the first sub-section; and / or the protective coating is at least partially disposed on the second sub-section.

[0025] In the above solution, when the insulating body includes a first subsection and a second subsection, the protective coating can be selectively applied to the surface of either the first subsection or the second subsection, or the protective coating can be applied to the surfaces of both subsections simultaneously. In other words, the embodiments of the present application can selectively apply the protective coating to a portion of the insulating body or to all of the insulating body based on the different expansion degrees of conventional plastic at different locations, thereby providing greater flexibility and practicality.

[0026] In some embodiments, the protective coating includes a first section located on the side of the insulating body facing the electrode body, a second section located on the side of the insulating body away from the electrode body, and a third section located on the peripheral side of the insulating body, and the third section is integrally connected to the second section relative to the first section.

[0027] In the above solution, the protective coating is partially located on the side of the insulating body facing the electrode body, and partially located on the side of the insulating body facing away from the electrode body, as well as on the surrounding side of the insulating body. This helps to further improve the protective coating's coverage of the insulating body and reduce contact between the electrolyte and the insulating body. Furthermore, because the side of the insulating body facing away from the electrode body can be covered by the second section, in certain application scenarios, such as when the battery cell is placed upside down during use, the provision of the second section can effectively prevent the electrolyte from reaching the insulating body. Therefore, in certain specific scenarios, this design can effectively alleviate the expansion of the insulating member and improve the reliability of the battery cell.

[0028] In some embodiments, the thickness of the protective coating is less than the thickness of the insulating body.

[0029] In the above solution, the protective coating has a smaller thickness than the insulating body. This helps reduce the protective coating's impact on the overall dimensions of the insulating component, lowers the risk of interference between the insulating component and other components within the housing, and improves the reliability of the battery cell's internal layout. Furthermore, a smaller thickness often translates to less weight. Therefore, setting the protective coating to a smaller thickness can reduce its adverse impact on the weight of the battery cell, thus enhancing practicality.

[0030] In some embodiments, the protective coating has a thickness H, where H satisfies: 0.2 μm ≤ H ≤ 1000 μm.

[0031] In the above solution, the thickness H of the protective coating is set to no less than 0.2 μm. This ensures that the protective coating has a certain thickness, effectively blocking the electrolyte. This reduces contact between the electrolyte and the insulating body, reduces the overall expansion of the insulating component, and improves the reliability and service life of the battery cell. Furthermore, the thickness H of the protective coating is set to no more than 1000 μm, thereby reducing the impact of the protective coating on the overall size and weight of the insulating component, ensuring the reliability of the internal layout of the battery cell and enhancing practicality.

[0032] In some embodiments, H satisfies: 50 μm≤H≤200 μm.

[0033] In the above solution, by further limiting the thickness dimension H of the protective coating to no less than 50 μm, the expansion deformation of the insulating component caused by the electrolyte can be further reduced, thereby improving the reliability and service life of the battery cell. Furthermore, since the varying thickness dimensions H of the protective coating have little effect on the expansion deformation of the insulating component when the thickness H is greater than 200 μm, limiting the thickness dimension H of the protective coating to no more than 200 μm effectively mitigates the expansion deformation of the insulating component while further reducing the impact of the protective coating on the internal space of the housing and the weight of the battery cell. This has strong practicality and also helps reduce the material cost of the protective coating.

[0034] In a second aspect, an embodiment of the present application provides a battery device, which includes a battery cell according to any of the aforementioned embodiments.

[0035] In a third aspect, an embodiment of the present application provides an electrical device, which includes the battery device in any of the aforementioned embodiments.

[0036] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0039] Figure 2 is a schematic structural diagram of a battery device provided in some embodiments of the present application;

[0040] Figure 3 is a schematic structural diagram of a battery module in a battery device provided in some embodiments of the present application;

[0041] Figure 4 This is a schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application;

[0042] Figure 5 is a schematic diagram of the positional relationship between a wall portion and an insulating member in a battery cell provided in some embodiments of the present application;

[0043] Figure 6 is a schematic structural diagram of an electrode terminal in an electric field cell provided in some embodiments of the present application;

[0044] Figure 7 is a schematic diagram of a cross-sectional structure of an electric field monomer provided by some embodiments of the present application;

[0045] Figure 8 1 is a schematic diagram of an enlarged structure of an electric field monomer in region Q provided by some embodiments of the present application;

[0046] Figure 9 1 is a schematic diagram of an enlarged structure of an electric field monomer at a region P provided by some embodiments of the present application;

[0047] Figure 10 1 is a schematic diagram of the cross-sectional structure of an electric field monomer provided in some embodiments of the present application.

[0048] Tag Name:

[0049] Vehicle 1000; battery device 100; controller 200; motor 300; housing 400; first housing portion 401; second housing portion 402; housing portion 403; battery cell 500; battery module 600;

[0050] Shell 10; wall 11; injection hole 12; electrode assembly 20; electrode body 21; electrode tab 22; insulating member 30; insulating body 31; first sub-section 311; second sub-section 312; protective coating 32; first sub-section 321; second sub-section 322; third sub-section 323; through-hole structure 33; injection channel 34; electrode terminal 40; current collecting member 50; thickness direction X. DETAILED DESCRIPTION

[0051] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0053] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0054] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0055] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0056] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0057] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, it is mentioned that the method may also include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0058] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0059] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0060] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0061] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0062] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0063] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0064] A battery cell typically includes an electrode assembly. This assembly consists of a positive electrode, a negative electrode, and a separator, which is positioned between the positive and negative electrodes. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing the active ions to pass through.

[0065] 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.

[0066] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0067] As examples, the positive electrode current collector can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, the metal foil can be made of pure metals, alloys, or surface-treated metals, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. A composite current collector can include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0068] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also referred to as NCM333), LiNi0.5Co0.2Mn0.3O2 (also referred to as NCM523), LiNi0.5Co At least one of LiNi0.6Co0.2Mn0.2O2 (also referred to as NCM622), LiNi0.8Co0.1Mn0.1O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi0.8Co0.15Al0.05O2), and modified compounds thereof. Modified compounds refer to substances obtained by modifying the above substances through methods such as doping or coating.

[0069] In some embodiments, a metal foam may be used as the positive electrode. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When the metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, the positive electrode active material may be filled and / or deposited within the metal foam.

[0070] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0071] As examples, the negative electrode current collector can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, the metal foil can be made of pure metal, alloy, or surface-treated metal, including but not limited to stainless steel, copper, aluminum, nickel, nickel, titanium, or silver. A composite current collector can include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0072] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0073] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0074] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0075] In some embodiments, the negative electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. When the metal foam is used as the negative electrode sheet, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0076] As an example, the negative electrode active material may be filled and / or deposited in the negative electrode current collector.

[0077] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0078] In some embodiments, the battery cell further includes an electrolyte, which acts as an ion conductor between the positive and negative electrodes. The present application does not specifically limit the type of electrolyte, which can be selected based on needs. The electrolyte may include an electrolyte salt and a solvent.

[0079] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0080] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be an ether solvent. Ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0081] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, or additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high temperature performance of the battery cell, and additives that improve the low temperature performance of the battery cell.

[0082] The electrode assembly may be a wound structure, a laminated structure, or a mixed structure of wound and laminated structures.

[0083] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0084] In some embodiments, the electrode assembly is a laminate structure.

[0085] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0086] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0087] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0088] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0089] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0090] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0091] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive electrode tab and a negative electrode tab.

[0092] In some embodiments, a battery cell may include an outer shell. This outer shell may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film. In some embodiments, the outer shell may be sealed or non-sealed. For example, in a non-sealed outer shell, the outer shell protects the electrode assembly and includes a sealing bag between the outer shell and the electrode assembly, which encapsulates the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating member or an aluminum-plastic film. In a sealed outer shell, the outer shell encapsulates the electrode assembly, electrolyte, and other components.

[0093] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in this application.

[0094] In some embodiments, the housing includes an end cap and a shell, wherein the shell has an opening and the end cap covers the opening. The shell may have one or more openings. One or more end caps may also be provided.

[0095] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to the tab. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via a current collecting member. The electrode terminal may be provided on an end cap or on the housing.

[0096] In some embodiments, the battery cell further includes a lower plastic member disposed on the side of the end cap facing the interior of the housing. The lower plastic member may be prefabricated from a single piece of plastic or assembled from various plastic components. The lower plastic member may be made of an insulating material to provide insulation, thereby enhancing electrical insulation between the components within the housing and the end cap. Furthermore, the lower plastic member may be disposed in contact with the electrode assembly to secure and protect it, thereby reducing the risk of short circuits caused by displacement of the electrode assembly and other components during transportation and use of the battery cell, particularly in vibration environments.

[0097] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, parallel, or hybrid via a busbar.

[0098] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells.

[0099] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing multiple battery cells to form an independent module. As an example, the battery module may be formed by bundling multiple battery cells with a cable tie.

[0100] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case.

[0101] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0102] As an example, the battery cell assembly may also be housed in the box by directly fixing the plurality of battery cells to the box.

[0103] As an example, the housing may include a first housing and a second housing. The first housing and the second housing engage to form an enclosed space within the housing to house the battery cell assembly. Enclosed here means covered or closed, and can be either sealed or unsealed. The first housing may be a top cover or a bottom plate.

[0104] As an example, the box may include a top cover, a frame, and a bottom plate, wherein the top cover and the bottom plate are respectively connected to the frame to form a closed space inside the box to accommodate the battery cell assembly.

[0105] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0106] In some embodiments, the battery device may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0107] The lower plastic is usually made of materials such as polypropylene, which has high impact resistance, strong mechanical properties, resistance to corrosion by various organic solvents and acids and alkalis, controllable costs, and does not produce toxic and harmful substances during use and degradation. However, during use, although the lower plastic does not chemically react with the electrolyte, the electrolyte will penetrate into the lower plastic, causing the lower plastic to swell. The "swelling" here refers to the phenomenon that the solvent molecules of the electrolyte diffuse into the interior of the lower plastic, causing the lower plastic to expand in volume. Under the combined influence of the swelling phenomenon and the action of gravity, the lower plastic will bulge downward and squeeze the electrode assembly, affecting the normal use of the electrode assembly, and thus affecting the operational reliability of the battery cell.

[0108] In view of this, embodiments of the present application provide a battery cell, a battery device, and an electrical device. The insulating member is further provided with a protective coating on the basis of the insulating body. The protective coating has a low electrolyte swelling degree, so even if the protective coating comes into contact with the electrolyte, it will not excessively expand. Furthermore, the protective coating is at least partially located on the side of the insulating body facing the electrode body. Therefore, the presence of the protective coating can also hinder contact between the surface of the insulating body facing the electrode body and the electrolyte, thereby achieving an effective barrier effect on the electrolyte, thereby reducing the degree of expansion of the insulating body, reducing the degree of compression of the electrode assembly by the insulating member, and improving the reliability of the battery cell.

[0109] The technical solutions described in the embodiments of this application are applicable to battery cells, battery devices, and electrical devices using the battery devices. Electrical devices can take various forms, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, vehicles, ships, and spacecraft, for example, including aircraft, rockets, space shuttles, and spacecraft.

[0110] The battery device described in the embodiments of the present application is not limited to being applicable to the electrical devices described above, but for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0111] See also Figure 1 , Figure 1A simple schematic diagram of a vehicle 1000 provided in an embodiment of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 may be provided inside the vehicle 1000. Specifically, for example, the battery device 100 may be provided at the bottom, front or rear of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000. For example, the battery device 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used, for example, to control the battery to power the motor 300. The battery device 100 may be used for starting and navigating the vehicle 1000. Of course, the battery device 100 may also be used to drive the vehicle 1000, replacing or partially replacing fuel or natural gas to provide drive for the vehicle 1000.

[0112] Please refer to Figure 2 , Figure 2 Exploded view of a battery device according to some embodiments of the present application. The battery device 100 includes a housing 400 and battery cells (not shown). The battery cells are housed within the housing 400. The housing 400 is used to house the battery cells and can have various structures. In some embodiments, the housing 400 can include a first housing portion 401 and a second housing portion 402. The first housing portion 401 and the second housing portion 402 overlap each other and together define a housing portion 403 for accommodating the battery cells. The second box portion 402 can be a hollow structure with one end open, and the first box portion 401 is a plate-like structure. The first box portion 401 covers the open side of the second box portion 402 to form a box with a storage portion 403. The first box portion 401 and the second box portion 402 can also be hollow structures with one end open, and the open side of the first box portion 401 covers the open side of the second box portion 402 to form the box 400 with a storage portion. Of course, the first box portion 401 and the second box portion 402 can be of various shapes, such as a cylinder, a cuboid, etc.

[0113] In the battery device 100, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within the housing 400. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 600, and then the battery modules 600 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within the housing 400.

[0114] Figure 3 for Figure 2FIG. 6 is a schematic diagram of an exploded structure of a battery module 600. In some embodiments, as Figure 3 As shown, there are multiple battery cells 500, which are first connected in series, in parallel, or in series to form a battery module 600. The multiple battery modules 600 are then connected in series, in parallel, or in series to form a whole, which is then housed in a box.

[0115] Next, the structure of the battery cell will be described with reference to the accompanying drawings. Figures 4 to 8 The battery cell 500 includes a housing 10, an electrode assembly 20, an electrode terminal 40, an electrolyte, and an insulating member 30. The housing 10 includes a wall portion 11. The electrode assembly 20 is disposed within the housing 10. The electrode assembly 20 includes an electrode body 21 and a tab 22 extending from the electrode body 21. The electrode terminal 40 is disposed in the wall portion 11 and electrically connected to the tab 22. The electrolyte is contained within the housing 10.

[0116] The insulating member 30 is arranged between the wall portion 11 and the electrode body 21. The insulating member 30 includes an insulating body 31 and a protective coating 32 arranged on the surface of the insulating body 31. The protective coating 32 is at least partially arranged on the side of the insulating body 31 facing the electrode body 21. The electrolyte swelling degree of the protective coating 32 is less than the electrolyte swelling degree of the insulating body 31.

[0117] The outer shell 10 is a shell structure within the battery cell 500 that houses and protects other components. The outer shell 10 is hollow and includes multiple wall structures, with the wall portion 11 being one of the wall structures on the outer shell 10. Optionally, the outer shell 10 includes a housing and an end cap, the housing having an opening, and the end cap being fitted over the opening of the housing. The wall portion 11 may be the end cap, or may be a wall structure on the housing. The accompanying drawings illustrate the case where the wall portion 11 is an end cap.

[0118] The electrode assembly 20 is disposed within the housing 10. The electrode assembly 20 is the core component of the battery cell 500 for achieving charge and discharge functions. The electrode assembly 20 includes an electrode body 21 and a tab 22. The electrode body 21 is the main component of the electrode assembly 20, and the tab 22 is the component of the electrode assembly 20 for electrically connecting to the electrode terminal 40. The electrode assembly 20 may include two tabs 22, at least one of which extends from the end of the electrode body 21 facing the wall 11 to achieve electrical connection with the electrode terminal 40 located on the wall 11.

[0119] The electrode terminal 40 is used to electrically connect the battery cell 500 to other external structures and is fixed to the wall portion 11. The electrode terminal 40 is electrically connected to the tab 22. The electrode terminal 40 can be directly connected to the tab 22, or the battery cell 500 can include a current collecting member 50, and the electrode terminal 40 can be indirectly connected to the tab 22 through the current collecting member 50.

[0120] The embodiments of the present application can be applied to various types of battery cells 500. For example, the battery cell 500 in the embodiments of the present application can be a cylindrical battery cell 500, that is, the outer shell 10 has a cylindrical structure. Or the battery cell 500 in the embodiments of the present application can be a square battery cell 500, that is, the outer shell 10 has a square structure. In addition, for different battery cells 500, the positional relationship of the electrode terminal 40 relative to the wall portion 11 may be different. For example, in the thickness direction X of the wall portion 11, the electrode terminal 40 may be partially or entirely provided on the side of the wall portion 11 facing away from the electrode body 21, or the electrode terminal 40 may also be partially or entirely provided in the electrode lead-out hole in the wall portion 11, or the electrode terminal 40 may also be partially located on the side of the wall portion 11 facing the electrode body 21.

[0121] The electrolyte is a carrier that realizes the ion transmission function in the battery cell 500. The electrolyte can play a role in conducting ions between the positive electrode plate and the negative electrode plate in the electrode assembly 20. For example, the electrolyte can include an electrolyte salt and a solvent.

[0122] The insulating member 30 is a component comprising insulating material and disposed within the housing 10. The insulating member 30 is disposed between the wall portion 11 and the electrode body 21. The insulating member 30 is provided to provide electrical insulation between the wall portion 11 and the electrode assembly 20. Furthermore, the insulating member 30 is disposed in contact with the electrode body 21 to secure and protect the electrode assembly 20, thereby reducing the risk of positional displacement of the electrode assembly 20 relative to the housing 10. For example, the insulating member 30 may be a lower plastic structure.

[0123] In order to improve the reliability of the battery cell 500, the embodiment of the present application adjusts the structural composition of the insulating part 30. Specifically, the insulating part 30 includes an insulating body 31 and a protective coating 32. The insulating body 31 is the main component structure of the insulating part 30, which can be made of conventional plastic materials, such as polyethylene. The protective coating 32 is a coating structure in the insulating part 30 that protects the insulating body 31. There can be various positional relationships between the protective coating 32 and the insulating body 31. For example, the protective coating 32 can be partially or completely located on the side of the insulating body 31 facing the electrode body 21, or the protective coating 32 can also be partially located on the side of the insulating body 31 away from the electrode body 21, or the protective coating 32 can also be partially located on the outer peripheral side of the insulating body 31, as long as the protective coating 32 is at least partially located on the side of the insulating body 31 facing the electrode body 21.

[0124] The protective coating 32 and the insulating body 31 are made of different materials and have different electrolyte swelling degrees. "Electrolyte swelling degree" refers to the degree to which a structure expands in an electrolyte under certain temperature, pressure, and chemical conditions. A higher electrolyte swelling degree indicates that the electrolyte more easily penetrates the structure, making it more susceptible to expansion. A lower electrolyte swelling degree indicates that the electrolyte is less likely to penetrate the structure, making it less susceptible to expansion.

[0125] On this basis, the embodiment of the present application controls the material composition of the protective coating 32 so that the electrolyte swelling degree of the protective coating 32 is smaller than that of the insulating body 31. On the one hand, this design can reduce the penetration of excessive electrolyte into the protective coating 32 and reduce the expansion degree of the protective coating 32. On the other hand, since the protective coating 32 is arranged on the outer surface of the insulating body 31, in the area where the protective coating 32 is provided, the electrolyte needs to pass through the protective coating 32 before entering the interior of the insulating body 31. Therefore, the provision of the protective coating 32 can have a blocking effect on the electrolyte entering the insulating body 31, reduce the contact between the electrolyte and the insulating body 31, and thereby reduce the expansion degree of the insulating body 31 in at least some areas.

[0126] Furthermore, since the protective coating 32 is at least partially located on the side of the insulating body 31 facing the electrode body 21, the presence of the protective coating 32 can hinder the contact between the surface of the insulating body 31 facing the electrode body 21 and the electrolyte, thereby reducing the degree of expansion of the insulating part 30 on the side close to the electrode body 21, reducing the degree of extrusion of the insulating part 30 on the electrode assembly 20, and improving the operating reliability of the electrode assembly 20 and the use reliability of the battery cell 500.

[0127] It should be noted that the structure of the protective coating 32 located on the side of the insulating body 31 facing the electrode body 21 can have various sizes and forms. It can completely cover the side surface of the insulating body 31 facing the electrode body 21, or the insulating body 31 can also be fitted with only a partial area of ​​the side surface of the insulating body 31 facing the electrode body 21.

[0128] In addition, the swelling degree of the structure can be obtained by testing using a specific method. For example, the test can be performed as follows: take an appropriate amount of sample corresponding to the structure to be tested, with the mass denoted as m1, place it in a semipermeable membrane sample bag, and seal it. The sample bag is permeable to the electrolyte but not to the sample; soak the sample bag in the electrolyte under specific constant temperature conditions for 7 days, then take out the sample bag, wipe off the excess electrolyte on the surface of the sample, and weigh the mass of the sample again, m2; in this case, the swelling degree corresponding to the structure is (m2-m1) / m1×100%.

[0129] In summary, in the embodiment of the present application, a protective coating 32 is added to the insulating member 30. The protective coating 32 has a low electrolyte swelling degree. Therefore, even if the protective coating 32 comes into contact with the electrolyte, the protective coating 32 will not expand excessively. Furthermore, the protective coating 32 is at least partially located on the side of the insulating body 31 facing the electrode body 21. Therefore, the presence of the protective coating 32 can also hinder the contact between the surface of the insulating body 31 facing the electrode body 21 and the electrolyte, thereby achieving an effective barrier effect on the electrolyte, thereby reducing the expansion of the insulating body 31. Therefore, without increasing or changing the internal mechanical structure of the battery cell 500, the degree of compression of the electrode assembly 20 by the insulating member 30 is reduced, thereby improving the reliability of the battery cell 500.

[0130] In some embodiments, the electrolyte swelling degree of the protective coating 32 is a, and a satisfies a≤0.1%. Alternatively, a is one of 0.1%, 0.05%, 0.01%, 0.005%, and 0.001%.

[0131] In an embodiment of the present application, the material composition of the protective coating 32 is adjusted so that the electrolyte swelling degree a of the protective coating 32 is not greater than 0.1%. This can not only reduce the expansion degree of the protective coating 32, but also improve the barrier effect of the protective coating 32 on the electrolyte, thereby hindering the contact between the insulating body 31 and the electrolyte, reducing the expansion degree of the insulating body 31, reducing the degree of extrusion of the insulating part 30 on the electrode assembly 20, and improving the reliability of the battery cell 500.

[0132] In some embodiments, protective coating 32 includes an organic material.

[0133] In the embodiments of the present application, at least some organic materials have low surface energy, or low surface tension, which makes it difficult for solvent molecules to adhere to their surfaces, thereby effectively preventing solvent penetration. Given this, the embodiments of the present application include protective coating 32 comprising an organic material, thereby imparting low surface energy to the protective coating 32. This reduces electrolyte penetration, reduces expansion of the protective coating 32, and minimizes contact between the electrolyte and the insulating body 31, thereby reducing overall expansion of the insulating member 30 and improving the reliability of the battery cell 500.

[0134] Furthermore, the protective coating 32 may optionally include an organic polymer material. Organic polymer materials are lightweight, have good mechanical and electrical properties, are corrosion-resistant, are easy to process, and are designable. By including the organic polymer material in the protective coating 32, the overall performance of the insulating member 30 can be improved.

[0135] In some embodiments, the organic material is polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), liquid crystal polymer (PPS), polyimide (PI), or fluororubber (Viton).

[0136] The above material can be formed on the surface of the insulating body 31 through an electrophoresis process. Specifically, polytetrafluoroethylene resin particles can be suspended in an electrolytic solution. The insulating body 31 is then placed in the electrolytic solution. The particles are deposited on the lower plastic surface by the action of an electric field. The protective coating 32 is then dried and solidified to form a uniform protective coating 32. Finally, the electrophoresis time is controlled to maintain a fixed thickness of the dried protective coating 32. In this way, the protective coating 32 including polytetrafluoroethylene can be present on the surface of the insulating body 31.

[0137] In the embodiments of the present application, polytetrafluoroethylene, polyether ketone, polyphenylene sulfide, liquid crystal polymer, polyimide, and fluororubber are all low-surface-energy materials. For example, the protective coating 32 is made of polytetrafluoroethylene. Polytetrafluoroethylene has a compact molecular structure and extremely low surface energy, making it difficult for electrolyte to penetrate. Specifically, the core component of polytetrafluoroethylene is a thin film with pores much smaller than the diameter of the droplet. Therefore, it is difficult for the electrolyte to penetrate the protective coating 32. Even if the protective coating 32 comes into contact with the electrolyte, the electrolyte will not cause the protective coating 32 to expand excessively. Furthermore, the protective coating 32 prevents the electrolyte from reaching the insulating body 31, thereby reducing the overall expansion of the insulating member 30.

[0138] Furthermore, polytetrafluoroethylene (PTFE) exhibits high-temperature resistance, chemical stability, high insulation, and scratch resistance. Furthermore, when applied to the protective coating 32, only a thin layer of PTFE is required to provide an effective barrier, mitigating operational reliability risks to the electrode assembly 20 caused by expansion of the insulating member 30. This design preserves the existing mechanical design within the battery cell 500 while also barely increasing the overall weight of the battery cell 500, ensuring a balanced performance of the battery cell 500.

[0139] In order to verify the improvement effect of the protective coating 32 on the expansion degree of the insulating member 30, the embodiment of the present application conducted an experimental test on the battery cell 500. Specifically, under the ambient temperature of 25°C, the battery cells 500 with and without the protective coating 32 were charged to 3.65V at a constant current of 1 / 3C, then charged to a current of 0.05C at a constant voltage of 3.65V, left for 5 minutes, and then discharged to 2.5V at 1 / 3C and left for 2 hours to simulate the actual use of the battery cell 500 under normal circumstances. Completing all the above processes is considered a full cycle. After 200 cycles, the maximum deformation of the insulating member 30 due to swelling is confirmed by CT imaging or actual disassembly. Among them, the maximum deformation mentioned here refers to: the dimensional change of the insulating member 30 after swelling in a specific direction relative to that before swelling. Further optionally, the maximum deformation can be the dimensional change of the insulating member 30 after swelling relative to that before swelling in the thickness direction X of the wall portion 11. The specific test results are as follows:

[0140]

[0141] It can be seen from the above test results that the protective coating 32 can effectively reduce the maximum deformation of the insulating member 30. At the same time, the protective coating 32 provided with polytetrafluoroethylene has better anti-swelling properties. This is due to the high and stable bond energy of the CF bond in polytetrafluoroethylene, the helical configuration of the molecule, and the CC main chain being completely shielded by the larger fluorine atoms.

[0142] In some embodiments, as Figure 4 and Figure 8 As shown, in the thickness direction X of the wall portion 11, at least a portion of the protective coating 32 is located between the insulating body 31 and the electrode tab 22. In other words, the projection of the structure of the protective coating 32 located on the insulating body 31 toward the electrode body 21 in the thickness direction X of the wall portion 11 overlaps with the projection of the electrode tab 22 in the thickness direction X.

[0143] In the related art, when the lower plastic expands due to the electrolyte, the lower plastic may contact the tab 22 and cause the tab 22 to sink, thereby compressing the space of the tab 22. The squeezed tab 22 may be inserted between adjacent pole pieces in the electrode body 21, thereby causing the risk of short circuit and heating, and affecting the reliability of the battery cell 500.

[0144] In the embodiment of the present application, at least a portion of the protective coating 32 is provided on the side of the insulating body 31 facing the electrode body 21, and the protective coating 32 may correspond to the position of the tab 22 and be sandwiched between the insulating body 31 and the tab 22. In this design, the presence of the protective coating 32 can reduce the degree of expansion of the portion of the insulating body 31 corresponding to the tab 22, thereby reducing the compression of the tab 22 by the insulating member 30, reducing the risk of the tab 22 sinking and being inserted into the interior of the electrode body 21, and improving the reliability of the battery cell 500.

[0145] In some embodiments, as Figure 4 and Figure 8 As shown, the battery cell 500 further includes a current collecting member 50, which is connected between the electrode terminal 40 and the tab 22. In the thickness direction X of the wall portion 11, at least a portion of the protective coating 32 is located between the insulating body 31 and the current collecting member 50. In other words, the projection of the structure of the protective coating 32 located on the insulating body 31 toward the electrode body 21 in the thickness direction X of the wall portion 11 overlaps with the projection of the current collecting member 50 in the thickness direction X.

[0146] The current collecting component 50 is a component structure used to realize electrical connection between the electrode tab 22 and the electrode terminal 40. A through-hole structure 33 may be provided on the insulating part 30. The through-hole structure 33 is arranged corresponding to the electrode lead-out hole on the wall portion 11. The current collecting component 50 and the electrode terminal 40 are contact-connected through the through-hole structure 33 and the electrode lead-out hole.

[0147] The current collecting member 50 and the insulating member 30 are typically close in the thickness direction X of the wall portion 11. When the insulating member 30 expands due to the electrolyte, the insulating member 30 easily contacts and squeezes the current collecting member 50, causing deformation of the current collecting member 50. Furthermore, since the current collecting member 50 is directly connected to the tab 22, deformation of the current collecting member 50 can squeeze the tab 22, thereby affecting the reliability of the battery cell 500.

[0148] In view of this, the embodiment of the present application arranges at least a portion of the protective coating 32 in a position corresponding to the current collecting member 50, and is sandwiched between the insulating body 31 and the current collecting member 50. With this design, the presence of the protective coating 32 can reduce the degree of expansion of the portion of the insulating body 31 corresponding to the current collecting member 50, thereby reducing the compression of the current collecting member 50 by the insulating element 30, thereby reducing the impact of the tab 22 sinking, and improving the reliability of the battery cell 500.

[0149] It should be noted that Figure 4The figure only illustrates the relative position relationship of the current collecting member 50 relative to the electrode assembly 20, the insulating member 30 and other structures, and does not constitute a limitation on the shape and size of the current collecting member 50, that is, the current collecting member 50 is not necessarily limited to a plate-like structure. According to the different types of battery cells 500, the current collecting member 50 can have a variety of different shapes. For example, in a cylindrical battery cell 500, the current collecting member 50 can be bent to form a three-section structure.

[0150] In some embodiments, in the thickness direction X of the wall portion 11, the insulating body 31 penetrates to form a through-hole structure 33, and the through-hole structure 33 is arranged corresponding to the electrode terminal 40. At least a portion of the protective coating 32 is arranged around the circumference of the through-hole structure 33; and / or, the protective coating 32 is partially arranged on the sidewall of the through-hole structure 33. Figure 8 FIG. 3 shows a case where the protective coating 32 is provided around the periphery of the through hole 33 .

[0151] The through-hole structure 33 penetrates the insulating body 31 along the thickness direction X of the wall portion 11. The through-hole structure 33 is arranged corresponding to the electrode terminal 40, that is, in the same projection plane perpendicular to the thickness direction X of the wall portion 11, the orthographic projection of the through-hole structure 33 and the orthographic projection of the electrode terminal 40 overlap. The through-hole structure 33 is designed to achieve electrical connection between the tab 22 and the electrode terminal 40. Depending on the type of battery cell 500, a current collecting member 50 may be provided inside the battery cell 500. In this case, the current collecting member 50 may pass through the through-hole structure 33 and be connected to the tab 22 and the electrode terminal 40 respectively. Alternatively, the current collecting member 50 may not be provided inside the battery cell 500. In this case, the tab 22 may pass through the through-hole structure 33 and be directly connected to the electrode terminal 40.

[0152] In the related art, the lower plastic tends to expand more significantly near the electrode terminals 40. This is because during use of the battery cell 500, the current density increases dramatically near the electrode terminals 40 due to a reduced flow area, generating greater heat and causing a localized temperature rise. Furthermore, due to the increasing demand for high energy and high power in battery cells 500, the capacity and charge / discharge current designs of battery cells 500 are also on the rise. Therefore, the expansion problem of the lower plastic near the electrode terminals 40 becomes increasingly severe.

[0153] In view of this, the embodiment of the present application further limits the position of the protective coating 32, and at least a portion of the protective coating 32 is arranged around the circumference of the through-hole structure 33, or the protective coating 32 is partially arranged on the side wall of the through-hole structure 33. In this way, at least a portion of the structure of the protective coating 32 can be located near the area corresponding to the electrode terminal 40, thereby hindering the contact between the insulating body 31 and the electrolyte in the area near the electrode terminal 40, thereby reducing the degree of expansion and deformation of the insulating part 30 in the area near the electrode terminal 40, and improving the structural reliability of the insulating part 30.

[0154] In some embodiments, as Figure 5 、 Figure 6 and Figure 8 As shown, the wall portion 11 is formed with a liquid injection hole 12 along its thickness direction X, and the insulating body 31 is formed with a liquid injection channel 34 along the thickness direction X of the wall portion 11. Within the same projection plane perpendicular to the thickness direction X of the wall portion 11, the orthographic projection of the liquid injection channel 34 is at least partially located outside the orthographic projection of the protective coating 32.

[0155] The injection hole 12 is provided in the wall portion 11 for injecting electrolyte into the interior of the housing 10. The injection channel 34 is provided in the insulating body 31. During the injection process, the electrolyte can flow through the injection channel 34 to the area where the electrode assembly 20 is located. There are various positions between the injection hole 12 and the injection channel 34. Optionally, within the same projection plane perpendicular to the thickness direction X of the wall portion 11, the orthographic projection of the injection hole 12 overlaps with the orthographic projection of the injection channel 34.

[0156] Furthermore, in the embodiment of the present application, the protective coating 32 is not arranged to cover the injection channel 34. In the same projection plane perpendicular to the thickness direction X of the wall 11, the entire projection of the injection channel 34 is at least partially located outside the positive projection of the protective coating 32. Under this design, the protective coating 32 will not completely block the injection channel 34. In this way, during the injection process, the protective coating 32 will not excessively hinder the flow of the electrolyte, thereby reducing the risk of long-term accumulation of the electrolyte at the insulating body 31 during the injection process, reducing the risk of excessive expansion of the insulating part 30 during the injection process, and improving the preparation yield of the battery cell 500.

[0157] It should be noted that the protective coating 32 and the injection channel 34 can have various positions. For example, within the same projection plane perpendicular to the thickness direction X of the wall portion 11, the orthographic projection of the injection channel 34 can be completely outside the orthographic projection of the protective coating 32, or the orthographic projection of the injection channel 34 can partially overlap with the orthographic projection of the protective coating 32. Furthermore, the protective coating 32 can be partially attached to the sidewall of the injection channel 34.

[0158] In some embodiments, see Figures 7 to 9The insulating body 31 includes a first sub-portion 311 and a second sub-portion 312, which are connected together. The second sub-portion 312 protrudes from the first sub-portion 311 on the side facing the electrode body 21. In the thickness direction X of the wall 11, the projection of the second sub-portion 312 is located outside the projection of the electrode tab 22. The protective coating 32 is at least partially disposed on the first sub-portion 311; and / or the protective coating 32 is at least partially disposed on the second sub-portion 312.

[0159] The first sub-portion 311 and the second sub-portion 312 are both made of insulating material and are fabricated together in the same process. In the thickness direction X of the wall portion 11, the projection of the first sub-portion 311 can overlap the projection of the tab 22, thereby insulating the tab 22 from the wall portion 11. For example, the first sub-portion 311 can be provided with a through-hole structure 33 to enable electrical connection between the electrode terminal 40 and the tab 22. Furthermore, the first sub-portion 311 can be provided with an injection channel 34 to meet the needs of electrolyte injection.

[0160] The second sub-portion 312 protrudes from a surface of the first sub-portion 311 facing the electrode body 21. The second sub-portion 312 can be located on a side of the through-hole structure 33 away from the center of the first sub-portion 311. That is, the second sub-portion 312 is arranged to protrude relative to the first sub-portion 311 at an edge region of the first sub-portion 311. Furthermore, the second sub-portion 312 is located on the outer periphery of the tab 22 and in the thickness direction X of the wall portion 11. The projection of the second sub-portion 312 overlaps with the projection of the edge region of the electrode body 21.

[0161] In the embodiment of the present application, when the insulating body 31 includes a first sub-section 311 and a second sub-section 312, the protective coating 32 can be selectively applied to the surface of either the first sub-section 311 or the second sub-section 312, or the protective coating 32 can be applied to the surfaces of both. In other words, the embodiment of the present application can selectively apply the protective coating 32 to a portion of or all of the insulating body 31, depending on the degree of expansion of conventional plastic at different locations. This provides greater flexibility and practicality.

[0162] It should be noted that the insulating member 30 can be disposed in contact with the electrode body 21 to reduce relative shaking between the electrode assembly 20 and the housing 10. Furthermore, when the second sub-portion 312 is provided with a protective coating 32, the protective coating 32 on the second sub-portion 312 can be disposed in contact with the electrode body 21, in which case the second sub-portion 312 is spaced apart from the electrode body 21. Alternatively, when the second sub-portion 312 is not provided with a protective coating 32, the second sub-portion 312 can be disposed directly in contact with the electrode body 21.

[0163] In some embodiments, see Figure 9 and Figure 10The protective coating 32 includes a first division 321 located on the side of the insulating body 31 facing the electrode body 21, a second division 322 located on the side of the insulating body 31 away from the electrode body 21, and a third division 323 located on the peripheral side of the insulating body 31. The third division 323 is integrally connected to the second division 322 relative to the first division 321.

[0164] The first subsection 321 is the portion of the protective coating 32 located on the side of the insulating body 31 facing the electrode body 21. The second subsection 322 is the portion of the protective coating 32 located on the side of the insulating body 31 facing the electrode body 21. The third subsection 323 is the portion of the protective coating 32 located on the circumferential side of the insulating body 31. The third subsection 323 is connected to the first subsection 321 and the second subsection 322 at both ends in the thickness direction X of the wall 11. The three subsections are integrally connected, i.e., comprised of the same material and formed in the same process.

[0165] Specifically, during the preparation of the insulating part 30, the prepared insulating body 31 can be completely placed in the electrolytic solution, and then the protective coating 32 can be formed on the surface of the insulating body 31 through an electrophoresis process. Under this process, the protective coating 32 can completely cover the surface of the insulating body 31, so that the protective coating 32 includes a first division 321, a second division 322 and a third division 323 located at different positions of the insulating body 31 and connected as a whole. This process is relatively simple and is conducive to controlling the thickness of the protective coating 32.

[0166] In the embodiment of the present application, the protective coating 32 is partially located on the side of the insulating body 31 facing the electrode body 21, and partially located on the side of the insulating body 31 facing away from the electrode body 21 and the surrounding side of the insulating body 31. This helps to further improve the covering and protection effect of the protective coating 32 on the insulating body 31 and reduce the contact between the electrolyte and the insulating body 31. Furthermore, since the side of the insulating body 31 facing away from the electrode body 21 can be covered by the second section 322, in certain application scenarios, such as when the battery cell 500 is placed upside down during use, the provision of the second section 322 can effectively prevent the electrolyte from reaching the insulating body 31. Therefore, in certain specific scenarios, this design can effectively alleviate the expansion of the insulating member 30 and improve the reliability of the battery cell 500.

[0167] In some embodiments, the thickness of the protective coating 32 is smaller than the thickness of the insulating body 31 .

[0168] It should be noted that the "thickness" mentioned here refers to the maximum thickness, that is, the maximum thickness of the protective coating 32 is less than the maximum thickness of the insulating body 31. The thickness of the insulating body 31 is the maximum dimension of the insulating body 31 in the thickness direction X of the wall portion 11. Since the protective coating 32 can be provided at different surface locations of the insulating body 31, the thickness of the protective coating 32 at different locations needs to be analyzed separately.

[0169] Specifically, taking the protective coating 32 as comprising a first subsection 321, a second subsection 322, and a third subsection 323, the thickness of the second subsection 322 is the maximum dimension of the second subsection 322 in the thickness direction X of the wall 11, and the thickness of the third subsection 323 is the maximum dimension of the third subsection 323 in the thickness direction X perpendicular to the wall 11. Regarding the first subsection 321, a portion of the structure in the first subsection 321 is aligned with the surfaces of the first subsection 311 and the second subsection 312 facing the electrode body 21, and thus the thickness of this portion of the structure is its maximum dimension in the thickness direction X of the wall 11. Other portions of the structure in the first subsection 321 are located on the side of the second subsection 312, and thus the thickness of this portion of the structure is its maximum dimension in the thickness direction X perpendicular to the side of the second subsection 312.

[0170] In the embodiment of the present application, the protective coating 32 has a smaller thickness than the insulating body 31. This helps reduce the impact of the protective coating 32 on the overall size of the insulating member 30, reduces the risk of interference between the insulating member 30 and other components within the housing 10, and improves the reliability of the internal layout of the battery cell 500. Furthermore, a smaller thickness often means less weight. Therefore, setting the protective coating 32 to have a smaller thickness can reduce its adverse impact on the weight of the battery cell 500, which has stronger practicality.

[0171] In some embodiments, see Figure 9 The protective coating layer 32 has a thickness H, where H satisfies: 0.2 μm ≤ H ≤ 1000 μm. Alternatively, H is one of 0.2 μm, 1 μm, 50 μm, 200 μm, 500 μm, and 1000 μm.

[0172] To verify the effect of the thickness of the protective coating 32 on the expansion of the insulating member 30, the present embodiment of the present invention conducted experimental tests on battery cells 500. Specifically, under two ambient temperature conditions of 25°C and 60°C, and with the protective coating 32 comprising polytetrafluoroethylene, battery cells 500 with protective coatings 32 of varying thicknesses were charged at a constant current of 1 / 3C to 3.65V, then charged at a constant voltage of 3.65V to a current of 0.05C, left for 5 minutes, and then discharged at a constant voltage of 1 / 3C to 2.5V, left for 2 hours, to simulate the actual use of battery cells 500 under normal circumstances. Completing the entire process described above constitutes one complete cycle. After 200 cycles, the maximum deformation of the insulating member 30 due to swelling was confirmed by CT imaging or actual disassembly. The specific test results are as follows:

[0173]

[0174] The table above shows that, within a certain thickness range, the greater the thickness of the protective coating 32, the smaller the maximum deformation of the insulating member 30. When the protective coating 32 is 0.2 μm thick, the corresponding maximum deformation of the insulating member 30 is 3.2 mm. This compares to the maximum deformation of the lower plastic in related art, which has been experimentally measured to be 3.2 mm. When H is not less than 0.2 μm, it can mitigate the expansion deformation of the insulating member 30.

[0175] In the embodiment of the present application, the thickness H of the protective coating 32 is set to be no less than 0.2 μm. This ensures that the protective coating 32 has a certain thickness, thereby effectively blocking the electrolyte. This reduces contact between the electrolyte and the insulating body 31, reduces the overall expansion of the insulating member 30, and improves the reliability and service life of the battery cell 500. Furthermore, the thickness H of the protective coating 32 is set to no more than 1000 μm, thereby reducing the impact of the protective coating 32 on the overall size and weight of the insulating member 30, ensuring the reliability of the internal layout of the battery cell 500 and providing strong practicality.

[0176] In some embodiments, H satisfies: 50 μm≤H≤200 μm. Alternatively, H is one of 50 μm, 75 μm, 100 μm, 150 μm, and 200 μm.

[0177] As can be seen from the table above, in the embodiment of the present application, by further limiting the thickness dimension H of the protective coating 32 to no less than 50 μm, the expansion deformation of the insulating member 30 caused by the electrolyte can be further reduced, thereby improving the reliability and service life of the battery cell 500. Furthermore, since the different thickness dimensions H of the protective coating 32 have little effect on the expansion deformation of the insulating member 30 when the thickness H of the protective coating 32 is greater than 200 μm, the thickness dimension H of the protective coating 32 is limited to no more than 200 μm. This effectively mitigates the expansion deformation of the insulating member 30 while further reducing the impact of the protective coating 32 on the internal space of the housing 10 and the weight of the battery cell 500. This has strong practicality and also helps reduce the material cost of the protective coating 32.

[0178] In a second aspect, an embodiment of the present application provides a battery device, which includes a battery cell 500 according to any of the aforementioned embodiments.

[0179] It should be noted that the battery device provided in the embodiment of the present application has the beneficial effects of the battery cell 500 in any of the aforementioned embodiments. Please refer to the aforementioned description of the beneficial effects of the battery cell 500 for details, and the embodiment of the present application will not be repeated.

[0180] In a third aspect, an embodiment of the present application provides an electrical device, which includes the battery device in any of the aforementioned embodiments.

[0181] According to some embodiments of this application, please refer to Figure 4 、 Figure 5 、 Figure 8 as well as Figure 9 The battery cell 500 includes a housing 10, an electrode assembly 20, an electrode terminal 40, an electrolyte, an insulating member 30, and a current collecting member 50. The housing 10 includes a wall 11. The electrode assembly 20 is disposed within the housing 10. The electrode assembly 20 includes an electrode body 21 and a tab 22 extending from the electrode body 21. The electrode terminal 40 is disposed within the wall 11 and electrically connected to the tab 22. The current collecting member 50 is connected between the electrode terminal 40 and the tab 22. The electrolyte is contained within the housing 10. The insulating member 30 is disposed between the wall 11 and the electrode body 21. The insulating member 30 includes an insulating body 31 and a protective coating 32 formed on the surface of the insulating body 31. The protective coating 32 has a lower electrolyte swelling than the insulating body 31.

[0182] The protective coating 32 includes an organic material such as polytetrafluoroethylene, polyether ketone, polyphenylene sulfide, liquid crystal polymer, polyimide or fluororubber. The thickness of the protective coating 32 is less than the thickness of the insulating body 31 .

[0183] In the thickness direction X of the wall portion 11, at least a portion of the protective coating 32 is located between the insulating body 31 and the electrode tab 22, and at least a portion of the protective coating 32 is located between the insulating body 31 and the current collecting member 50. The insulating body 31 is penetrated to form a through-hole structure 33, which is arranged corresponding to the electrode terminal 40. The protective coating 32 is partially arranged around the circumference of the through-hole structure 33 and partially arranged on the sidewalls of the through-hole structure 33.

[0184] The wall portion 11 is penetrated along its thickness direction X to form an injection hole, and the insulating body 31 is penetrated in the thickness direction X of the wall portion 11 to form an injection channel 34. In the same projection plane perpendicular to the thickness direction X of the wall portion 11, the orthographic projection of the injection channel 34 is at least partially located outside the orthographic projection of the protective coating 32.

[0185] The insulating body 31 includes a first sub-portion 311 and a second sub-portion 312 that are connected as a whole. The second sub-portion 312 protrudes from the first sub-portion 311 toward the electrode body 21, and in the thickness direction X of the wall 11, the projection of the second sub-portion 312 is located outside the projection of the pole ear 22. The protective coating 32 is partially arranged on the first sub-portion 311 and partially arranged on the second sub-portion 312.

[0186] The protective coating 32 includes a first section 321 located on the side of the insulating body 31 facing the electrode body 21, a second section 322 located on the side of the insulating body 31 away from the electrode body 21, and a third section 323 located on the circumferential side of the insulating body 31. The third section 323 is integrally connected to the second section 322 relative to the first section 321.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: a housing including a wall portion; an electrode assembly disposed in the housing, the electrode assembly comprising an electrode body and a tab extending from the electrode body; an electrode terminal, disposed on the wall portion and electrically connected to the electrode tab; an electrolyte contained in the housing; An insulating member is arranged between the wall portion and the electrode body, and the insulating member includes an insulating body and a protective coating arranged on the surface of the insulating body. The protective coating is at least partially arranged on the side of the insulating body facing the electrode body, and the electrolyte swelling degree of the protective coating is less than the electrolyte swelling degree of the insulating body.

2. The battery cell according to claim 1, wherein: The electrolyte swelling degree of the protective coating is a, and a satisfies: a≤0.1%.

3. The battery cell according to claim 1, wherein: The protective coating includes an organic material.

4. The battery cell according to claim 3, characterized in that The organic material is polytetrafluoroethylene, polyether ketone, polyphenylene sulfide, liquid crystal polymer, polyimide or fluororubber.

5. The battery cell according to claim 1, characterized in that In a thickness direction of the wall portion, at least a portion of the protective coating is located between the insulating body and the tab.

6. The battery cell according to claim 5, characterized in that The battery cell further includes a current collecting member connected between the electrode terminal and the tab; At least a portion of the protective coating layer is located between the insulating body and the current collecting member in a thickness direction of the wall portion.

7. The battery cell according to claim 1, characterized in that In the thickness direction of the wall portion, the insulating body is penetrated to form a through-hole structure, and the through-hole structure is arranged corresponding to the electrode terminal; At least a portion of the protective coating is disposed around the periphery of the through-hole structure; and / or a portion of the protective coating is disposed on the sidewall of the through-hole structure.

8. The battery cell according to claim 1, wherein: The wall portion is penetrated along its thickness direction to form a liquid injection hole, and the insulating body is penetrated along the thickness direction of the wall portion to form a liquid injection channel; In the same projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the liquid injection channel is at least partially located outside the orthographic projection of the protective coating.

9. The battery cell according to claim 1, characterized in that The insulating body includes a first sub-portion and a second sub-portion connected as one body, the second sub-portion protruding from the first sub-portion toward the electrode body, and the projection of the second sub-portion in the thickness direction of the wall portion is located outside the projection of the electrode tab; The protective coating is at least partially disposed on the first sub-portion; and / or the protective coating is at least partially disposed on the second sub-portion.

10. The battery cell according to claim 1, characterized in that The protective coating comprises a first section located on a side of the insulating body facing the electrode body, a second section located on a side of the insulating body facing away from the electrode body, and a third section located on a peripheral side of the insulating body; The third sub-section is arranged opposite to the first sub-section and is integrally connected with the second sub-section.

11. The battery cell according to claim 1, wherein The thickness of the protective coating is smaller than the thickness of the insulating body.

12. The battery cell according to claim 11, characterized in that The thickness of the protective coating is H, and H satisfies: 0.2 μm≤H≤1000 μm.

13. The battery cell according to claim 12, characterized in that: H satisfies: 50μm≤H≤200μm.

14. A battery device, characterized in that: The utility model comprises a busbar component and the battery cell according to any one of claims 1 to 12.

15. An electrical device, characterized in that: Comprising the battery device of claim 14.

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