A battery cell, a battery device, and an electric device
By designing the interlayer peel strength range of the first and second adhesive layers of the separator in the battery cell, the problem of uneven bonding strength between the separator and the electrode is solved, achieving good adhesion and reliability of the battery cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CONTEMPORARY AMPEREX TECHNOLOGY CO LTD
- Filing Date
- 2025-01-14
- Publication Date
- 2026-07-14
Smart Images
Figure CN122393559A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery device technology, and in particular to a battery cell, a battery device, and an electrical device. Background Technology
[0002] Battery devices have advantages such as high specific energy and high power density, and are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships and power tools.
[0003] As battery devices are applied to more and more fields, improving the reliability of battery devices is receiving increasing attention from those skilled in the art. Summary of the Invention
[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, wherein the battery cell has good reliability.
[0005] In a first aspect, some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The electrode assembly is housed in the casing and includes a separator and a first electrode and a second electrode with opposite polarities. The separator includes a base layer, a first adhesive layer, and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively disposed on two surfaces of the base layer that are disposed opposite to each other in the thickness direction. The first electrode, the separator, and the second electrode are stacked along the thickness direction. The first adhesive layer is bonded to the first electrode, and the second adhesive layer is bonded to the second electrode. The interlayer peel strength between the first adhesive layer and the first electrode is A, and the interlayer peel strength between the second adhesive layer and the second electrode is B, where 10N / m≤A≤35N / m and 10N / m≤B≤35N / m.
[0006] According to some embodiments of this application, a battery cell is provided in which a first electrode, a separator, and a second electrode are wound along a winding direction; the separator includes a starting region and a winding region connected along the winding direction, the starting region is connected to the starting end of the separator, the density of the first adhesive layer in the starting region is greater than the density of the first adhesive layer in the winding region, and the density of the second adhesive layer in the starting region is greater than the density of the second adhesive layer in the winding region.
[0007] According to some embodiments of the present application, the number of turns of the separator winding is C, the number of turns of the starting area winding is D, and 5% ≤ D / C ≤ 15%.
[0008] According to some embodiments of this application, the battery cell has a first electrode sheet as a positive electrode sheet and a first adhesive layer comprising polyvinylidene fluoride; and a second electrode sheet as a negative electrode sheet and a second adhesive layer comprising styrene-butadiene rubber.
[0009] According to some embodiments of this application, the battery cell includes a first separator and a second separator. The first separator is located inside the second separator. The first electrode, the first separator, the second electrode, and the second separator are stacked sequentially along the thickness direction. Along the winding direction, the length of the first separator is longer than the length of the first electrode and the length of the second electrode. The length of the second separator is longer than the length of the second electrode and the length of the first separator. The second adhesive layer of the second separator at the winding end is bonded to the first adhesive layer of the second separator located in the inner ring.
[0010] According to some embodiments of the present application, the number of turns of the second separator is G, the number of turns of the first separator is H, and 0.2≤G﹣H≤0.8.
[0011] According to some embodiments of this application, the battery cell includes a winding region comprising a first region and a second region connected along the winding direction, the first region being connected to the starting region and the second region, and the second region being connected to the end of the separator being wound; the first electrode is a positive electrode, the second electrode is a negative electrode, and in the second region, the first adhesive layer comprises a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the second adhesive layer comprises polyacrylic acid.
[0012] According to some embodiments of the present application, in the second region, the first adhesive layer includes a first sublayer and a second sublayer. The first sublayer is disposed on the surface of the substrate, and the second sublayer is disposed on the surface of the first sublayer away from the substrate. The second adhesive layer includes a third sublayer and a fourth sublayer. The third sublayer is disposed on the surface of the substrate, and the fourth sublayer is disposed on the surface of the third sublayer away from the substrate. The second sublayer includes a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the fourth sublayer includes polyacrylic acid.
[0013] According to some embodiments of this application, the battery cell has a second sub-layer connected to the end of the separator winding, a fourth sub-layer connected to the end of the separator winding, the number of turns of the second sub-layer winding is E, 0.5≤F≤1; the number of turns of the fourth sub-layer winding is F, 1≤F≤2.
[0014] According to some embodiments of this application, the battery cell includes an electrode assembly comprising a flat region and two oppositely arranged bent regions, the flat region being connected between the two bent regions, and the end of the coiled separator being located in the flat region.
[0015] Secondly, some embodiments of this application provide a battery device that includes a single battery cell provided by any of the above-described technical solutions.
[0016] Thirdly, some embodiments of this application provide an electrical device that includes the battery device provided by the above-described technical solutions.
[0017] The technical solutions provided by the embodiments of this application bring at least the following beneficial effects:
[0018] Some embodiments of this application provide a battery cell, which includes a casing and an electrode assembly. The electrode assembly is housed in the casing and includes a separator and a first electrode and a second electrode with opposite polarities. The separator includes a base layer, a first adhesive layer, and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively disposed on two surfaces of the base layer that are disposed opposite to each other in the thickness direction. The first electrode, the separator, and the second electrode are stacked along the thickness direction. The first adhesive layer is bonded to the first electrode, and the second adhesive layer is bonded to the second electrode. The interlayer peel strength between the first adhesive layer and the first electrode is A, and the interlayer peel strength between the second adhesive layer and the second electrode is B, where 10N / m≤A≤35N / m and 10N / m≤B≤35N / m. In the above structure, since the first adhesive layer of the separator is bonded to the first electrode and the interlayer peel strength A between the separator and the first electrode is in the range of 10N / m≤A≤35N / m, and the second adhesive layer of the separator is bonded to the second electrode and the interlayer peel strength B between the separator and the second electrode is in the range of 10N / m≤B≤35N / m, the separator has good adhesive strength with both the first and second electrodes. During the charging and discharging process of the battery cell, the separator can fit well with the first and second electrodes, is not prone to wrinkles, and maintains good performance of the battery cell, thus having good reliability.
[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0020] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:
[0021] Figure 1 Flowcharts of vehicles provided for some embodiments of this application;
[0022] Figure 2 This is a schematic diagram showing the disassembled structure of a battery device provided in some embodiments of this application;
[0023] Figure 3 This is a schematic diagram of the disassembled structure of a battery cell provided in some embodiments of this application;
[0024] Figure 4 Cross-sectional views of electrode assemblies provided in some embodiments of this application;
[0025] Figure 5 for Figure 4 The image shows a magnified view of K in some embodiments;
[0026] Figure 6 for Figure 4 The middle K is an enlarged view in some other embodiments.
[0027] In the diagram:
[0028] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Receiving space; 7. Battery cell; 8. Shell; 9. Electrode assembly; 91. Separator; 911. Base layer; 912. First adhesive layer; 9121. First sub-layer; 9122. Second sub-layer; 913. Second adhesive layer; 9131. Third sub-layer; 9132. Fourth sub-layer; 914. First separator; 915. Second separator; 92. First electrode; 93. Second electrode; 94. Straight area; 95. Bending area; 10. Starting area; 20. Winding area; X. Winding direction. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0030] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.
[0031] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.
[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0033] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.
[0034] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.
[0035] In the embodiments of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering. For example, if the angle between two directions is 85°-90°, the two directions can be considered perpendicular; if the angle between two directions is 0°-5°, the two directions can be considered parallel.
[0036] In this application, "multiple" means two or more (including two).
[0037] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields.
[0038] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cell assemblies to provide higher voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.
[0039] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.
[0040] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.
[0041] Battery cells can be lithium-ion cells, sodium-ion cells, sodium-lithium-ion cells, lithium metal cells, sodium metal cells, lithium-sulfur cells, magnesium-ion cells, nickel-metal hydride cells, nickel-cadmium cells, lead-acid cells, etc.
[0042] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.
[0043] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.
[0044] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.
[0045] As an example, the positive current collector can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).
[0046] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as 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 phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide 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, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.
[0047] In some embodiments, the negative electrode can be a negative electrode sheet, which may include a negative electrode current collector.
[0048] As an example, the negative current collector can be made of metal foil, conductive polymer material, carbon material, or composite current collector. For example, as a metal foil, pure metal, alloy, or surface-treated metal can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).
[0049] 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.
[0050] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.
[0051] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. 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, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.
[0052] In some embodiments, the negative electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.
[0053] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.
[0054] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.
[0055] The insulating element is placed between the positive and negative electrodes.
[0056] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.
[0057] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.
[0058] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.
[0059] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.
[0060] Liquid electrolytes include electrolyte salts and solvents.
[0061] 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 difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.
[0062] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may 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, methyl tetrahydrofuran, diphenyl ether, and crown ethers.
[0063] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and 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.
[0064] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.
[0065] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.
[0066] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.
[0067] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.
[0068] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.
[0069] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.
[0070] The separator is placed between any two adjacent positive or negative electrode plates.
[0071] As an example, the separator can be continuously arranged and placed between any adjacent positive or negative electrode plates by winding.
[0072] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.
[0073] In addition to isolating electrons and transporting lithium ions, the separator in the electrode assembly also needs to provide adhesion, ensuring tight contact and bonding between the positive and negative electrode sheets and the separator, thus guaranteeing a consistent lithium ion transport path. Currently, the same adhesive is typically used to bond the separator to both the positive and negative electrode sheets. However, due to the significant differences in materials between the positive and negative electrode sheets, the adhesion strength between the adhesive and the two sheets varies considerably. Generally, the adhesive bonds well to the positive electrode but poorly to the negative electrode. This makes the battery cell prone to wrinkles and bubbles during use, affecting its performance and reducing its reliability.
[0074] To improve the reliability of a single battery cell, this application provides a single battery cell including a casing and an electrode assembly. The electrode assembly is housed in the casing and includes a separator and a first electrode and a second electrode with opposite polarities. The separator includes a base layer, a first adhesive layer, and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively disposed on two surfaces of the base layer that are opposite to each other in the thickness direction. The first electrode, the separator, and the second electrode are stacked along the thickness direction. The first adhesive layer is bonded to the first electrode, and the second adhesive layer is bonded to the second electrode. The interlayer peel strength between the first adhesive layer and the first electrode is A, and the interlayer peel strength between the second adhesive layer and the second electrode is B, where 10N / m≤A≤35N / m and 10N / m≤B≤35N / m. In the above structure, since the first adhesive layer of the separator is bonded to the first electrode and the interlayer peel strength A between the separator and the first electrode is in the range of 10N / m≤A≤35N / m, and the second adhesive layer of the separator is bonded to the second electrode and the interlayer peel strength B between the separator and the second electrode is in the range of 10N / m≤B≤35N / m, the separator has good adhesive strength with both the first and second electrodes. During the charging and discharging process of the battery cell, the separator can fit well with the first and second electrodes, is not prone to wrinkles, and maintains good performance of the battery cell, thus having good reliability.
[0075] The battery cells described in this application are applicable to battery devices and electrical devices that use battery devices. The battery devices disclosed in this application can be used in electrical devices that use battery devices as a power source or in various energy storage systems that use battery devices as energy storage elements.
[0076] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, among others. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.
[0077] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.
[0078] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.
[0079] like Figure 1As shown, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.
[0080] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.
[0081] In some embodiments of this application, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.
[0082] Figure 2 This is a schematic diagram showing the disassembled structure of a battery device provided in some embodiments of this application. For example... Figure 2 As shown, the battery device 2 includes a housing 5 and battery cells 7, with the battery cells 7 housed within the housing 5. The battery cell 7 can be the smallest unit that makes up a battery.
[0083] The housing 5 is used to house the battery cell 7, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the battery cell 7. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can be various shapes, such as cylinders, cuboids, etc.
[0084] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.
[0085] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.
[0086] In the battery device 2, there can be one or more battery cells 7. If there are multiple battery cells 7, they can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 7 are connected in both series and parallel. Multiple battery cells 7 can be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 7 is housed in the housing 5. Alternatively, multiple battery cells 7 can first be connected in series, in parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in a mixed manner to form a whole assembly, which is then housed in the housing 5.
[0087] The battery cell 7 can be a cylindrical battery cell, a square battery cell, or a battery cell of other shapes.
[0088] Some embodiments of this application provide a battery cell 7, see reference Figure 3 The battery cell 7 includes a housing 8 and an electrode assembly 9, the electrode assembly 9 being housed within the housing 8, as referenced. Figure 4 The electrode assembly 9 includes an insulating member 91 and a first electrode 92 and a second electrode 93 with opposite polarities, as shown in the reference. Figure 5 The separator 91 includes a base layer 911, a first adhesive layer 912, and a second adhesive layer 913. The first adhesive layer 912 and the second adhesive layer 913 are respectively disposed on two surfaces of the base layer 911 that are opposite to each other in the thickness direction. The first electrode 92, the separator 91, and the second electrode 93 are stacked along the thickness direction. The first adhesive layer 912 is bonded to the first electrode 92, and the second adhesive layer 913 is bonded to the second electrode 93. The interlayer peel strength between the first adhesive layer 912 and the first electrode 92 is A, and the interlayer peel strength between the second adhesive layer 913 and the second electrode 93 is B. 10N / m≤A≤35N / m, 10N / m≤B≤35N / m.
[0089] The outer casing 8 can have various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the outer casing 8 can be determined according to the specific shape and size of the electrode assembly 9. The outer casing 8 can be made of various materials, such as copper, iron, aluminum, stainless steel, or aluminum alloy. The electrode assembly 9 is the component in the battery cell 7 where the electrochemical reaction takes place. The outer casing 8 can contain one or more electrode assemblies 9.
[0090] The electrodes can be wound or stacked in the electrode assembly 9. The first electrode 92 and the second electrode 93 are electrodes with opposite polarities, one being a positive electrode and the other a negative electrode. The separator 91 is a component disposed between the first electrode 92 and the second electrode 93 to prevent short circuits between the negative and positive electrodes, while allowing active ions to pass through. The first electrode 92, the separator 91, and the second electrode 93 are stacked along the thickness direction of the separator 91, such that the first electrode 92 and the second electrode 93 are respectively disposed on opposite sides of the separator 91 along its thickness direction, so that the separator 91 prevents short circuits between the first electrode 92 and the second electrode 93.
[0091] The base layer 911 can be the matrix structure layer in the separator 91, which can serve as a carrier for functional layers such as adhesive layers and provide channels for active ions to pass through the separator 91. The first adhesive layer 912 and the second adhesive layer 913 are adhesive layers disposed on two surfaces of the base layer 911 that are opposite to each other in the thickness direction. The first adhesive layer 912 can be a structural layer of the separator 91 used to bond with the first electrode 92, and the second adhesive layer 913 can be a structural layer of the separator 91 used to bond with the second electrode 93.
[0092] Since the first electrode 92 and the second electrode 93 are made of different materials, the bonding strength between the first electrode 92 and the second electrode 93 and the same adhesive material is different. The first adhesive layer 912 and the second adhesive layer 913 can be formed using different adhesive materials so that the bonding strength between the first adhesive layer 912 and the second adhesive layer 913 and the first electrode 92 and the second electrode 93, which are made of different materials, can be similar and meet the requirements.
[0093] By setting the range of the interlayer peel strength A between the first adhesive layer 912 and the first electrode 92 to 10 N / m ≤ A ≤ 35 N / m, the bonding strength between the first adhesive layer 912 and the first electrode 92 is sufficient to maintain a stable fit, while also avoiding excessively high material requirements for the first adhesive layer 912 that would increase costs. This helps control the cost of the separator 91. Similarly, by setting the range of the interlayer peel strength B between the second adhesive layer 913 and the second electrode 93 to 10 N / m ≤ B ≤ 35 N / m, the bonding strength between the second adhesive layer 913 and the second electrode 93 is sufficient to maintain a stable fit, while also avoiding excessively high material requirements for the second adhesive layer 913 that would increase costs. This helps control the cost of the separator 91.
[0094] The interlayer peel strength between the first adhesive layer 912 and the first electrode 92, and the interlayer peel strength between the second adhesive layer 913 and the second electrode 93, can be determined according to the national standard GB / T 2792-2014. The specific determination method can be referred to the national standard GB / T 2792-2014, and will not be elaborated here.
[0095] In the above structure, since the first adhesive layer 912 of the separator 91 is bonded to the first electrode 92 and the interlayer peel strength A between the separator 91 and the first electrode 92 is in the range of 10N / m≤A≤35N / m, and the second adhesive layer 913 of the separator 91 is bonded to the second electrode 93 and the interlayer peel strength B between the separator 91 and the second electrode 93 is in the range of 10N / m≤B≤35N / m, the separator 91 has good adhesive strength with both the first electrode 92 and the second electrode 93. During the charging and discharging process of the battery cell 7, the separator 91 can fit well with the first electrode 92 and the second electrode 93, and is not prone to wrinkles, so that the battery cell 7 maintains good performance and has good reliability.
[0096] In some embodiments, the first electrode 92, the spacer 91, and the second electrode 93 are wound along the winding direction X; the spacer 91 includes a starting region 10 and a winding region 20 connected along the winding direction X, the starting region 10 is connected to the end of the spacer 91 where it starts to be wound, the density of the first adhesive layer 912 of the starting region 10 is greater than the density of the first adhesive layer 912 of the winding region 20; the density of the second adhesive layer 913 of the starting region 10 is greater than the density of the second adhesive layer 913 of the winding region 20.
[0097] The first electrode 92, the separator 91, and the second electrode 93 are wound along the winding direction X, so that the electrode assembly 9 has a wound structure, and the electrode assembly 9 can be wound to form.
[0098] The starting area 10 and the winding area 20 are different regions in the separator 91, and the starting area 10 and the winding area 20 are connected sequentially along the winding direction X. That is, the starting area 10 is located inside the electrode assembly 9 compared to the winding area 20. The starting area 10 is connected to the starting end of the separator 91, and the winding area 20 is connected to the winding end of the separator 91.
[0099] The density of the first adhesive layer 912 in the starting area 10 is greater than that in the winding area 20. This can be achieved by having more material forming the first adhesive layer 912 on the surface of the base layer 911 of the starting area 10 facing the first electrode 92 than on the surface of the base layer 911 of the winding area 20 facing the first electrode 92. This results in a higher density and stronger adhesion of the first adhesive layer 912 in the starting area 10, which is beneficial for improving the adhesion strength between the separator 91 and the first electrode 92 in the starting area 10.
[0100] The density of the second adhesive layer 913 in the starting area 10 is greater than that in the winding area 20. This can be achieved by having more material forming the second adhesive layer 913 on the surface of the base layer 911 of the starting area 10 facing the second electrode 93 than on the surface of the base layer 911 of the winding area 20 facing the second electrode 93. This results in a higher density and stronger adhesion of the second adhesive layer 913 in the starting area 10, which is beneficial for improving the adhesion strength between the separator 91 and the second electrode 93 in the starting area 10.
[0101] Because external heat and pressure are difficult to transfer to the core portion of the electrode assembly 9 during the hot-pressing process, the first adhesive layer 912 and the second adhesive layer 913 in the core portion are unlikely to swell to improve the bonding strength with the first electrode 92 and the second electrode 93. For example, the diameter of the electrode assembly 9 in the battery cell 7 can reach 30 mm. In this case, the heat and pressure of the hot-pressing process are difficult to transfer to the core portion of the electrode assembly 9, and the bonding between the separator 91 and the electrode in the core portion is relatively loose.
[0102] By setting the density of the first adhesive layer 912 in the winding area 10 to be greater than that in the winding area 20, and setting the density of the second adhesive layer 913 in the winding area 10 to be greater than that in the winding area 20, the separator 91 in the core portion of the electrode assembly 9 can be well bonded to the first electrode 92 and the second electrode 93. This facilitates good adhesion between the separator 91 in the core portion and the first electrode 92 and the second electrode 93, reducing the possibility of the separator 91 in the core portion detaching from the first electrode 92 or the second electrode 93 during the use of the battery cell 7, thus improving the reliability of the battery cell 7.
[0103] In some embodiments, the number of turns of the spacer 91 is C, and the number of turns of the starting area 10 is D, where 5% ≤ D / C ≤ 15%.
[0104] The separator 91 is wound in multiple layers, with the number of turns of the separator 91 being C and the number of turns of the starting area 10 being D. By setting the relationship between the number of turns of the separator 91 (C) and the number of turns of the starting area 10 (D) to 5% ≤ D / C ≤ 15%, the separator 91 located in the core part of the electrode assembly 9 can be bonded to the first electrode 92 and the second electrode 93 through the first adhesive layer 912 and the second adhesive layer 913, which have a higher density. This not only makes the structure of the core part of the electrode assembly 9 more firmly bonded, but also reduces the material waste of the first adhesive layer 912 and the second adhesive layer 913, which is beneficial to controlling the cost of the battery cell 7.
[0105] In some embodiments, 8% ≤ D / C ≤ 13%. For example, the ratio of the number of turns D of the winding in the starting area 10 to the number of turns C of the winding in the separator 91 can be 8%, 10%, and 13%, which makes the structure of the core portion of the electrode assembly 9 more firmly bonded while reducing material waste in the first adhesive layer 912 and the second adhesive layer 913, which is beneficial for controlling the cost of the battery cell 7.
[0106] For example, the spacer 91 can be wound 50 times, and the number of turns in the starting area 10 can be 5. Those skilled in the art can set the number of turns of the spacer 91 and the number of turns of the starting area 10 according to actual conditions.
[0107] In some embodiments, the first electrode 92 is a positive electrode, and the first adhesive layer 912 includes polyvinylidene fluoride; the second electrode 93 is a negative electrode, and the second adhesive layer 913 includes styrene-butadiene rubber.
[0108] Because polyvinylidene fluoride (PVDF) can better bond with the material of the positive electrode sheet. The first electrode sheet 92 is the positive electrode sheet. By including PVDF in the first adhesive layer 912, the first adhesive layer 912 can obtain better bonding strength with the positive electrode sheet, which improves the interlayer peel strength between the first adhesive layer 912 and the positive electrode sheet, and helps the first adhesive layer 912 meet the bonding requirements with the positive electrode sheet.
[0109] Because styrene-butadiene rubber (SBR) can better bond with the material of the negative electrode sheet. The first electrode sheet 92 is the negative electrode sheet. By including SBR in the second adhesive layer 913, the second adhesive layer 913 can obtain better bonding strength with the negative electrode sheet, which improves the interlayer peel strength between the second adhesive layer 913 and the negative electrode sheet, and helps the second adhesive layer 913 meet the bonding requirements with the negative electrode sheet.
[0110] For example, polyvinylidene fluoride powder can be dispersed in a polar organic solution such as N-methylpyrrolidone or dimethyl carbonate, and stirred at a temperature of 40°C-60°C to form a uniform solution with a concentration range of 10%-20%. The solution is then applied to the surface of the base film facing the first electrode 92 by spraying or roller coating. After the separator 91 is dried, a first adhesive layer 912 is formed on the surface of the base film facing the first electrode 92.
[0111] Styrene-butadiene rubber powder can be dispersed in deionized water and stirred to form a uniform solution with a concentration range of 10%-20%. The solution is then applied to the surface of the base film facing the second electrode 93 by spraying or roller coating. After the separator 91 is dried, a second adhesive layer 913 is formed on the surface of the base film facing the second electrode 93.
[0112] In some embodiments, the first adhesive layer 912 and the second adhesive layer 913 may be formed sequentially, or the first adhesive layer 912 and the second adhesive layer 913 may be dried and formed simultaneously.
[0113] In some embodiments, the spacer 91 includes a first spacer 914 and a second spacer 915. The first electrode 92, the first spacer 914, the second electrode 93, and the second spacer 915 are stacked sequentially along the thickness direction. Along the winding direction X, the length of the first spacer 914 is longer than the length of the first electrode 92 and the length of the second electrode 93, and the length of the second spacer 915 is longer than the length of the second electrode 93 and the length of the first spacer 914. The second adhesive layer 913 of the second spacer 915 at the winding end is bonded to the first adhesive layer 912 of the second spacer 915 located in the inner ring.
[0114] The separator 91 includes a first separator 914 and a second separator 915, wherein the first separator 914 is closer to the inner side of the electrode assembly 9 than the second separator 915. The first electrode 92, the first separator 914, the second electrode 93, and the second separator 915 are stacked sequentially along the thickness direction, so that the wound first electrode 92 and the second electrode 93 can be separated by the separator 91.
[0115] By setting the length of the first separator 914 along the winding direction X to be longer than the length of the first electrode 92 along the winding direction X and the length of the second electrode 93 along the winding direction X, the first separator 914 can effectively separate the first electrode 92 and the second electrode 93.
[0116] By setting the length of the second spacer 915 along the winding direction X to be longer than the length of the second electrode 93 and the length of the first spacer 914 along the winding direction X, the outermost second spacer 915 can cover the winding end of the second electrode 93, the winding end of the first spacer 914 and the winding end of the first electrode 92.
[0117] By bonding the second adhesive layer 913 of the second separator 915 at the winding end to the first adhesive layer 912 of the second separator 915 located in the inner ring, the second separator 915 can seal the winding ends of the second electrode 93, the winding ends of the first separator 914, and the winding ends of the first electrode 92 through the bonding with the second separator 915 in the inner ring. This eliminates the need for additional adhesive at the winding end, which not only simplifies the process and reduces costs, but also helps to reduce the thickness of the electrode assembly 9 and increase the energy density of the battery cell 7. Furthermore, it ensures that the winding ends of the separator 91 will not deflect under external force when the winding ends of the separator 91 are cut.
[0118] In some embodiments, the number of turns of the second spacer 915 is G, the number of turns of the first spacer 914 is H, and 0.2≤G﹣H≤0.8.
[0119] By setting the range where the number of turns G of the second spacer 915 is longer than the number of turns H of the first spacer 914 to 0.2≤G﹣H≤0.8, not only can the second spacer 915 effectively cover the ends of the second electrode 93, the first spacer 914, and the first electrode 92, but it also helps to reduce material waste caused by the second spacer 915 being too long.
[0120] In some embodiments, the number of turns G of the second spacer 915 being longer than the number of turns H of the first spacer 914 is set to be 0.25 ≤ G - H ≤ 0.75. For example, the number of turns G of the second spacer 915 being longer than the number of turns H of the first spacer 914 can be 0.3, 0.5, or 0.7. This not only ensures that the second spacer 915 can effectively cover the ends of the second electrode 93, the first spacer 914, and the first electrode 92, but also helps to reduce material waste caused by an excessively long second spacer 915.
[0121] In some embodiments, the winding region 20 includes a first region and a second region connected along the winding direction X. The first region is connected to the starting region 10 and the second region, and the second region is connected to the winding end of the separator 91. The first electrode 92 is a positive electrode, and the second electrode 93 is a negative electrode. In the second region, the first adhesive layer 912 includes a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the second adhesive layer 913 includes polyacrylic acid.
[0122] The first zone and the second zone are two interconnected areas in the winding zone 20. The first zone and the second zone are arranged sequentially along the winding direction X. The first zone is connected to the starting zone 10 and the second zone, and the second zone is connected to the end of the winding of the separator 91.
[0123] By setting the first electrode 92 as the positive electrode and the second electrode 93 as the negative electrode, and by making the first adhesive layer 912 of the second region include a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the second adhesive layer 913 of the second region include polyacrylic acid, not only can the first adhesive layer 912 containing the copolymer of polyvinylidene fluoride and hexafluoropropylene adhere well to the positive electrode, and the second adhesive layer 913 containing polyacrylic acid adhere well to the negative electrode, but also the second adhesive layer 913 of the second separator 915 at the winding end adheres to the first adhesive layer 912 of the second separator 915 located in the inner ring, and the second adhesive layer 913 of the second separator 915 at the winding end adheres to the first adhesive layer 912 of the second separator 915 located in the inner ring, the copolymer of polyvinylidene fluoride and hexafluoropropylene can combine with the polyacrylic acid, which is beneficial to improving the bonding strength between the first adhesive layer 912 and the second adhesive layer 913.
[0124] In some embodiments, reference Figure 6 In the second region, the first adhesive layer 912 includes a first sublayer 9121 and a second sublayer 9122. The first sublayer 9121 is disposed on the surface of the base layer 911, and the second sublayer 9122 is disposed on the surface of the first sublayer 9121 facing away from the base layer 911. The second adhesive layer 913 includes a third sublayer 9131 and a fourth sublayer 9132. The third sublayer 9131 is disposed on the surface of the base layer 911, and the fourth sublayer 9132 is disposed on the surface of the third sublayer 9131 facing away from the base layer 911. The second sublayer 9122 includes a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the fourth sublayer 9132 includes polyacrylic acid.
[0125] The first sublayer 9121 and the second sublayer 9122 are different structural layers of the first adhesive layer 912 in the second region. They can be made of different materials, giving them different properties and functions. The first sublayer 9121 is a structural layer of the first adhesive layer 912 disposed on the surface of the base layer 911. It can serve as the bottom layer of the first adhesive layer 912. By disposing of the second sublayer 9122 on the surface of the first sublayer 9121 facing away from the base layer 911, the surface of the first adhesive layer 912 in the second region used for bonding can be modified.
[0126] The third sublayer 9131 and the fourth sublayer 9132 are different structural layers of the second adhesive layer 913 in the second region. They can be made of different materials, giving them different properties and functions. The third sublayer 9131 is a structural layer in the second adhesive layer 913 disposed on the surface of the base layer 911. It can serve as the bottom layer of the fourth adhesive layer. By disposing of the fourth sublayer 9132 on the surface of the third sublayer 9131 facing away from the base layer 911, the surface of the second adhesive layer 913 in the second region used for bonding can be modified.
[0127] Since the fourth sublayer 9132 is disposed on the surface of the third sublayer 9131 away from the base layer 911, and the second sublayer 9122 is disposed on the surface of the first sublayer 9121 away from the base layer 911, the bonding between the second adhesive layer 913 of the second separator 915 at the winding end and the first adhesive layer 912 of the second separator 915 of the inner ring is the bonding between the second sublayer 9122 and the fourth sublayer 9132.
[0128] By including a copolymer of polyvinylidene fluoride and hexafluoropropylene in the second sublayer 9122 and polyacrylic acid in the fourth sublayer 9132, the copolymer of polyvinylidene fluoride and hexafluoropropylene can bond with the polyacrylic acid when the second sublayer 9122 and the fourth sublayer 9132 are bonded, thereby improving the bonding strength between the second sublayer 9122 and the fourth sublayer 9132.
[0129] For example, the first sublayer 9121 includes polyvinylidene fluoride, the first adhesive layer 912 of the first region includes polyvinylidene fluoride, and the first adhesive layer 912 of the roll-up region 10 includes polyvinylidene fluoride, so that the polyvinylidene fluoride structural layer on the surface of the separator 91 can be formed by the same spraying or roller coating process, which improves the convenience of forming the polyvinylidene fluoride structural layer.
[0130] The third sublayer 9131 includes styrene-butadiene rubber, the second adhesive layer 913 of the first region includes styrene-butadiene rubber, and the second adhesive layer 913 of the roll-up region 10 includes styrene-butadiene rubber, so that the styrene-butadiene rubber structural layer on the surface of the separator 91 can be formed by the same spraying or roller coating process, which improves the convenience of forming the styrene-butadiene rubber structural layer.
[0131] In some embodiments, the second sublayer 9122 is connected to the winding end of the spacer 91, and the fourth sublayer 9132 is connected to the winding end of the spacer 91. The number of turns of the second sublayer 9122 is E, 0.5≤F≤1; the number of turns of the fourth sublayer 9132 is F, 1≤F≤2.
[0132] By connecting the second sub-layer 9122 to the winding end of the spacer 91 and the fourth sub-layer 9132 to the winding end of the spacer 91, the second sub-layer 9122 and the fourth sub-layer 9132 are structural layers located at the winding point. By setting the range of the number of turns F of the fourth sub-layer 9132 to 1≤F≤2 and the range of the number of turns E of the second sub-layer 9122 to 0.5≤F≤1, the second sub-layer 9122 and the fourth sub-layer 9132 are bonded with 0.5 to 1 turns. This not only ensures a strong bond between the second sub-layer 9122 and the fourth sub-layer 9132, but also provides good bonding strength between the first adhesive layer 912 and the second adhesive layer 913 at the winding end. Furthermore, it helps reduce material waste caused by excessively long second sub-layers 9122 and 9132.
[0133] In some embodiments, the number of turns E of the second sub-layer 9122 is set to a range of 0.6 ≤ F ≤ 0.8, and the number of turns F of the fourth sub-layer 9132 is set to a range of 1 ≤ F ≤ 1.25. For example, the number of turns E of the second sub-layer 9122 can be set to 0.75, and the number of turns F of the fourth sub-layer 9132 can be set to 1, 1.1, or 1.25, so that the fourth sub-layer 9132 can be firmly bonded to the second sub-layer 9122 near the winding end. This not only ensures good bonding strength between the first adhesive layer 912 and the second adhesive layer 913 at the winding end, but also helps to reduce material waste caused by excessively long second sub-layers 9122 and 9132.
[0134] In some embodiments, the electrode assembly 9 includes a flat region 94 and two oppositely arranged bent regions 95, the flat region 94 being connected between the two bent regions 95, and the winding end of the spacer 91 being located in the flat region 94.
[0135] The straight region 94 can be a region with a straight structure in the winding structure formed after the first electrode 92, the separator 91 and the second electrode 93 are wound together, and the bent region 95 can be a bent region in the winding structure formed after the first electrode 92, the separator 91 and the second electrode 93 are wound together.
[0136] By connecting the straight region 94 between two oppositely arranged bent regions 95, the electrode assembly 9 is made into an elliptical cylindrical structure. The elliptical cylindrical electrode assembly 9 can be formed by hot pressing a cylindrical structure formed by winding the first electrode 92, the spacer 91, and the second electrode 93.
[0137] By setting the end of the winding of the spacer 91 in the flat region 94, the end of the winding of the spacer 91 can be well heated in the hot pressing process, and the second adhesive layer 913 and the first adhesive layer 912 are more likely to swell and bond firmly to the adjacent components.
[0138] Some embodiments of this application also provide a battery device 2, which includes the battery cell 7 provided by the above-described technical solution.
[0139] Since the battery device 2 includes the battery cell 7 provided by the above-mentioned technical solution, the battery device 2 has good reliability.
[0140] Some embodiments of this application also provide an electrical device, which includes the battery device 2 provided in the above-described technical solutions, the battery device 2 being used to provide electrical energy. The electrical device can be any of the electrical equipment provided in the foregoing technical solutions.
[0141] Some embodiments of this application provide a battery cell 7, which includes a housing 8 and an electrode assembly 9 housed in the housing 8. A first electrode 92, a separator 91, and a second electrode 93 are stacked and wound along the thickness direction of the separator 91. The separator 91 includes a base layer 911, a first adhesive layer 912, and a second adhesive layer 913. The first adhesive layer 912 and the second adhesive layer 913 are respectively disposed on two surfaces of the base layer 911 that are opposite to each other in the thickness direction. The first adhesive layer 912 is bonded to the first electrode 92, and the second adhesive layer 913 is bonded to the second electrode 93. The interlayer peel strength between the first adhesive layer 912, which includes polyvinylidene fluoride, and the first electrode 92 is A, and the interlayer peel strength between the second adhesive layer 913, which includes styrene-butadiene rubber, and the second electrode 93 is B. 10N / m≤A≤35N / m, 10N / m≤B≤35N / m. In the above structure, since the first adhesive layer 912 of the separator 91 is bonded to the first electrode 92 and the interlayer peel strength A between the separator 91 and the first electrode 92 is in the range of 10N / m≤A≤35N / m, and the second adhesive layer 913 of the separator 91 is bonded to the second electrode 93 and the interlayer peel strength B between the separator 91 and the second electrode 93 is in the range of 10N / m≤B≤35N / m, the separator 91 has good adhesive strength with both the first electrode 92 and the second electrode 93. During the charging and discharging process of the battery cell 7, the separator 91 can fit well with the first electrode 92 and the second electrode 93, and is not prone to wrinkles, so that the battery cell 7 maintains good performance and has good reliability.
[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A battery cell, characterized in that, include: shell; An electrode assembly is housed within the housing. The electrode assembly includes a spacer and a first electrode and a second electrode with opposite polarities. The spacer includes a base layer, a first adhesive layer, and a second adhesive layer. The first adhesive layer and the second adhesive layer are respectively disposed on two surfaces of the base layer that are opposite to each other in the thickness direction. The first electrode, the spacer, and the second electrode are stacked along the thickness direction. The first adhesive layer is bonded to the first electrode, and the second adhesive layer is bonded to the second electrode. The interlayer peel strength between the first adhesive layer and the first electrode is A, and the interlayer peel strength between the second adhesive layer and the second electrode is B, where 10 N / m ≤ A ≤ 35 N / m and 10 N / m ≤ B ≤ 35 N / m.
2. The battery cell according to claim 1, characterized in that, The first electrode, the separator, and the second electrode are wound along a winding direction; the separator includes a starting area and a winding area connected along the winding direction, the starting area is connected to the starting end of the separator, the density of the first adhesive layer in the starting area is greater than the density of the first adhesive layer in the winding area, and the density of the second adhesive layer in the starting area is greater than the density of the second adhesive layer in the winding area.
3. The battery cell according to claim 2, characterized in that, The number of turns of the separator is C, and the number of turns of the starting area is D, where 5% ≤ D / C ≤ 15%.
4. The battery cell according to any one of claims 1-3, characterized in that, The first electrode is a positive electrode, and the first adhesive layer includes polyvinylidene fluoride; the second electrode is a negative electrode, and the second adhesive layer includes styrene-butadiene rubber.
5. The battery cell according to claim 2, characterized in that, The isolation element includes a first isolation element and a second isolation element. The first isolation element is located inside the second isolation element. The first electrode, the first isolation element, the second electrode, and the second isolation element are stacked sequentially along the thickness direction. Along the winding direction, the length of the first isolation element is longer than the length of the first electrode and the length of the second electrode. The length of the second isolation element is longer than the length of the second electrode and the length of the first isolation element. The second adhesive layer of the second isolation element at the winding end is bonded to the first adhesive layer of the second isolation element located on the inner ring.
6. The battery cell according to claim 5, characterized in that, The number of turns of the second separator is G, and the number of turns of the first separator is H, where 0.2≤G﹣H≤0.
8.
7. The battery cell according to claim 5 or 6, characterized in that, The winding area includes a first area and a second area connected along the winding direction. The first area is connected to the starting area and the second area, and the second area is connected to the end of the separator being wound. The first electrode is a positive electrode, and the second electrode is a negative electrode. In the second area, the first adhesive layer includes a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the second adhesive layer includes polyacrylic acid.
8. The battery cell according to claim 7, characterized in that, In the second region, the first adhesive layer includes a first sublayer and a second sublayer, the first sublayer being disposed on the surface of the base layer, the second sublayer being disposed on the surface of the first sublayer facing away from the base layer, the second adhesive layer including a third sublayer and a fourth sublayer, the third sublayer being disposed on the surface of the base layer, the fourth sublayer being disposed on the surface of the third sublayer facing away from the base layer; the second sublayer includes a copolymer of polyvinylidene fluoride and hexafluoropropylene, and the fourth sublayer includes polyacrylic acid.
9. The battery cell according to claim 8, characterized in that, The second sub-layer is connected to the end of the winding of the separator, and the fourth sub-layer is connected to the end of the winding of the separator. The number of turns of the second sub-layer is E, 0.5≤F≤1; the number of turns of the fourth sub-layer is F, 1≤F≤2.
10. The battery cell according to any one of claims 5-9, characterized in that, The electrode assembly includes a flat region and two oppositely arranged bent regions, the flat region being connected between the two bent regions, and the end of the coiled spacer being located in the flat region.
11. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-10.
12. An electrical appliance, characterized in that, Includes the battery device as described in claim 11.