Insulating film, battery, battery device, and electric device

Abstract

The utility model provides an insulating film, a battery, a battery device and electric equipment. Relates to the technical field of batteries. The insulating film provided by the embodiment of the utility model is used for the battery. The insulating film includes a base layer and a first insulating coating layer. The first insulating coating is at least coated on the surface of one side of the base layer. The first insulating coating has a plurality of first openings. The porosity of the first insulating coating is P, and P is larger than or equal to 40% and smaller than or equal to 60%. The first insulating coating is arranged on the base layer, the first opening is formed in the first insulating coating, and the first opening is used for storing part of electrolyte in the electrolyte injection process. Therefore, a normal space for storing the electrolyte in the battery is removed, and the insulating film provides an additional space for storing the electrolyte, so that the electrolyte retention capacity of the insulating film is improved, the electrolyte retention capacity of the electrolyte in the battery is improved, the cycle performance of the battery is improved, the use performance of the battery device is improved, and the service life of electric equipment is prolonged.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and more particularly to an insulating film, a battery, a battery device, and an electrical device. Background Technology

[0002] A battery consists of a casing, a cell, and an insulating film, with the insulating film used to enclose the cell. The battery's cycle performance is related to the electrolyte retention capacity; under the same conditions and system, a higher electrolyte retention capacity generally results in better cycle performance. However, in current technology, batteries can only absorb electrolyte through the cell, leading to low cycle performance. Utility Model Content

[0003] The insulating film, battery, battery device, and electrical equipment provided in this application embodiment enable the insulating film to store electrolyte, thereby increasing the electrolyte retention capacity of the battery, improving the cycle performance of the battery, enhancing the performance of the battery device, and extending the service life of the electrical equipment.

[0004] In a first aspect, embodiments of this application provide an insulating film. For use in a battery, the insulating film includes a base layer and a first insulating coating. The first insulating coating is applied to at least one surface of the base layer. The first insulating coating has a plurality of first openings. The porosity of the first insulating coating is P, where P satisfies: 40% ≤ P ≤ 60%.

[0005] In some embodiments of this application, the aperture of the first opening is D, where D satisfies: 0.5μm≤D≤1.5μm.

[0006] In some embodiments of this application, the thickness of the first insulating coating is H1, where H1 satisfies: 3μm≤H1≤5μm.

[0007] In some embodiments of this application, the base layer includes a first surface located on one side in the thickness direction. A first insulating coating is applied to the first surface. The first surface is adapted to face the battery cell.

[0008] In some embodiments of this application, the thickness of the base layer is B, where B satisfies: 80μm≤B≤90μm.

[0009] In some embodiments of this application, the insulating film further includes a second insulating coating. The second insulating coating is applied to the side of the insulating coating opposite to the substrate. The second insulating coating has a second opening.

[0010] In some embodiments of this application, the thickness of the second insulating coating is H2, where H2 satisfies: 1μm≤H2≤2μm.

[0011] In some embodiments of this application, the insulating coating is made by mixing inorganic particles, a binder, and a dispersant. The mass ratio of the inorganic particles to the binder is M; M satisfies: 0.8 ≤ M ≤ 1.2.

[0012] The mass ratio of inorganic particles to dispersant is N, where N satisfies: 12.5 ≤ N ≤ 30. The mass ratio of binder to dispersant is O, where O satisfies: 12.5 ≤ O ≤ 30.

[0013] In some embodiments of this application, the inorganic particles include one or more of the following inorganic particle components: hafnium dioxide, silicon dioxide, tin dioxide, cerium dioxide, magnesium oxide, nickel oxide, calcium oxide, zinc oxide, aluminum oxide, zirconium dioxide, aluminum oxide, silicon carbide, and boehmite. When the inorganic particles include multiple inorganic particle components, the mass of each inorganic particle component is equal.

[0014] In some embodiments of this application, the adhesive includes one or more of the following adhesive components: polyvinylidene fluoride, polyacrylate, polyvinyl alcohol, polyacrylic acid, and polyimide.

[0015] When the adhesive comprises multiple adhesive components, the mass of each adhesive component is equal.

[0016] In some embodiments of this application, the dispersant includes one or more of the following dispersant components: sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, triethyl phosphate, polyacrylic acid, and sodium polyacrylate.

[0017] When the dispersant includes multiple dispersant components, the masses of each dispersant component are equal.

[0018] In some embodiments of this application, the base layer includes one or more of the following base layer components: polyethylene, polypropylene, and polyethylene terephthalate.

[0019] When the base layer includes multiple components, the mass of each component is equal.

[0020] In some embodiments of this application, the second insulating coating includes one or more of the following insulating components: polyvinylidene fluoride, polyacrylate, styrene-butadiene latex, and polyimide.

[0021] When the second insulating coating comprises multiple insulating components, the mass of each insulating component is equal.

[0022] Secondly, embodiments of this application provide a battery. The battery includes a cell and an insulating film, with the insulating film covering the cell.

[0023] In some embodiments of this application, the first insulating coating of the insulating film abuts against the battery cell.

[0024] In some embodiments of this application, the insulating film further includes a second insulating coating, which is applied to the side of the first insulating coating away from the base layer of the insulating film; the second insulating coating has a second opening, and the second insulating coating abuts against the battery cell.

[0025] Thirdly, embodiments of this application provide an electrical device, including a battery.

[0026] Fourthly, embodiments of this application provide an electrical device, including a battery or an electrical appliance.

[0027] This application provides an insulating film, a battery, a battery device, and an electrical appliance. The insulating film includes a base layer and a first insulating coating. The first insulating coating is applied to at least one surface of the base layer. The first insulating coating has a plurality of first openings. The porosity of the first insulating coating is P, where P satisfies: 40% ≤ P ≤ 60%. By providing the first insulating coating on the base layer and providing the first openings on the first insulating coating, the first openings are used to store a portion of the electrolyte during electrolyte injection. In this way, in addition to the space normally used for storing electrolyte in the battery, the insulating film provides additional space for electrolyte storage, increasing the electrolyte retention capacity in the battery, improving the battery cycle performance, improving the performance of the battery device, and increasing the service life of the electrical appliance. By setting the porosity P of the first openings on the first insulating coating to: 40% ≤ P ≤ 60%, the first insulating coating can provide sufficient space to store electrolyte, ensuring effective ion conduction. At the same time, when the porosity of the first insulating coating is within this range, the first insulating coating has a certain mechanical strength, preventing damage and deformation of the first insulating coating, thus improving the structural stability of the first insulating coating. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0029] Figure 1 A schematic diagram of the battery structure provided in the embodiments of this application. Figure 1 ;

[0030] Figure 2 A schematic diagram of the battery structure provided in the embodiments of this application. Figure 2 ;

[0031] Figure 3 A schematic diagram of the structure of the insulating film of the battery provided in the embodiments of this application. Figure 1 ;

[0032] Figure 4 A schematic diagram of the structure of the insulating film of the battery provided in the embodiments of this application. Figure 2 ;

[0033] Figure 5 A schematic diagram of the structure of the insulating film of the battery provided in the embodiments of this application. Figure 3 ;

[0034] Figure 6 This is a schematic diagram of the structure of the first insulating coating of the battery provided in an embodiment of this application;

[0035] Figure 7 Example 1 of the insulating film for the battery provided in this application;

[0036] Figure 8 for Figure 7 A schematic diagram of region A in the middle;

[0037] Figure 9 Example 2 of the insulating film for the battery provided in this application;

[0038] Figure 10 The graph shows the test results of the battery capacity retention rate and cycle life provided in the embodiments of this application.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100: Outer shell; 110: Shell body; 120: End cap; 130: Side plate structural component;

[0041] 200: Battery cell;

[0042] 300: Insulating film; 310: Base layer; 320: First insulating coating; 330: Second insulating coating. Detailed Implementation

[0043] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0044] In related technologies, Mylar insulating film is a polyester film with electrical insulation properties, heat resistance, and a certain degree of mechanical strength. Mylar insulating film is used to wrap the cells of prismatic aluminum-cased batteries. The Mylar insulating film acts as an insulator in the prismatic aluminum-cased battery, preventing short circuits between the cell and the aluminum casing, thus ensuring the battery's safety and stability.

[0045] A battery consists of a casing, a cell, and an insulating film, which encapsulates the cell. The cycle performance of a battery is related to the electrolyte retention capacity; under the same conditions and system, a higher electrolyte retention capacity generally results in better cycle performance.

[0046] However, in related technologies, batteries can only absorb electrolyte through the cell, resulting in low cycle performance.

[0047] Therefore, embodiments of this application provide an insulating film, a battery, a battery device, and an electrical appliance. The insulating film includes a base layer and a first insulating coating. The first insulating coating is applied to at least one surface of the base layer. The first insulating coating has a plurality of first openings. The porosity of the first insulating coating is P, where P satisfies: 40% ≤ P ≤ 60%. By providing the first insulating coating on the base layer and providing the first openings on the first insulating coating, the first openings are used to store a portion of the electrolyte during electrolyte injection. In this way, in addition to the space normally used for storing electrolyte in the battery, the insulating film provides additional space for electrolyte storage, increasing the electrolyte retention capacity in the battery, improving the battery cycle performance, improving the performance of the battery device, and increasing the service life of the electrical appliance. By setting the porosity P of the first openings on the first insulating coating to: 40% ≤ P ≤ 60%, the first insulating coating can provide sufficient space to store electrolyte, ensuring effective ion conduction. At the same time, when the porosity of the first insulating coating is within this range, the first insulating coating has a certain mechanical strength, which prevents the first insulating coating from being damaged and deformed. In this way, the structural stability and liquid retention capacity of the first insulating coating are improved.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] Firstly, embodiments of this application provide an electrical device, including a battery or battery assembly. The electrical device provided in this application can be implemented in various ways. For example, it can be a vehicle, ferry, energy storage cabinet, computer, aircraft, etc. This application does not limit the specific type of electrical device.

[0050] Secondly, embodiments of this application provide a battery device, including a battery. The battery device provided in this application has various implementations. For example, it can be a battery pack, battery cluster, battery module, etc.

[0051] Thirdly, embodiments of this application provide a battery. The battery includes a cell 200 and an insulating film 300, with the insulating film 300 covering the cell 200.

[0052] The first insulating coating 320 of the insulating film 300 abuts against the battery cell 200.

[0053] Exemplary examples show that the battery provided in this application has multiple implementation methods. For example, it can be a lithium-ion battery or a sodium-ion battery.

[0054] The battery also includes a housing 100, which has a cavity in which the battery cell 200 and an insulating film 300 are located.

[0055] For example, the housing 100 includes an aluminum casing. The aluminum casing provides external protection against physical shocks, vibrations, and compression, preventing damage to the battery cells 200 and other components inside the battery. Simultaneously, the aluminum casing effectively encapsulates the battery, preventing electrolyte leakage and the ingress of external contaminants such as moisture and dust. Furthermore, the aluminum casing is lightweight, enabling a lightweight design for electrical devices. The aluminum casing is also thermally conductive, aiding in battery heat dissipation and contributing to the battery's stability and safety during high-performance operation.

[0056] Reference Figure 1 and Figure 2 The housing includes a housing body 110 and an end cap 120. The housing body 110 has a cavity with openings at both ends. The end cap 120 closes to the openings. The housing 100 also includes a side plate structure 130. The side plate structure 130 may be a plate. The side plate structure 130 provides mechanical strength and protects the battery cells 200 and other components inside the battery from external impacts, vibrations, and physical damage.

[0057] The insulating film 300 is used for insulation between the battery cell 200 and the aluminum shell to prevent electrical short circuits between the battery cell 200 and the aluminum shell and improve the stability of the battery.

[0058] In one possible implementation, the insulating film 300 further includes a second insulating coating 330, which is applied to the side of the first insulating coating 320 away from the base layer 310 of the insulating film 300; the second insulating coating 330 has a second opening and abuts against the battery cell 200.

[0059] By providing a second insulating coating 330 on the side of the first insulating coating 320 facing away from the base layer 310, and by providing a second opening on the second insulating coating 330, the second insulating coating 330 can also be used to store electrolyte, further increasing the amount of electrolyte stored in the insulating film 300, thereby improving the battery's performance. In addition, the second insulating coating 330 can provide additional mechanical protection to prevent the battery from being damaged by physical impact or vibration.

[0060] Since the cycle performance of a battery is related to the electrolyte retention capacity, this application embodiment designs the structure of the insulating film 300 to further improve the electrolyte retention capacity in the battery. The following will take the battery casing 100 as an aluminum casing and the battery as a lithium-ion battery as an example to introduce the structure of the insulating film 300 in detail.

[0061] Fourthly, refer to Figures 3 to 6 This application provides an insulating film 300 for use in a battery. The insulating film 300 includes a base layer 310 and a first insulating coating 320. The first insulating coating 320 is coated on at least one side of the surface of the base layer 310. The base layer 310 provides the insulating film 300 with a certain mechanical strength and flexibility, enabling the insulating film 300 to withstand certain mechanical stress and deformation, and to be less prone to damage and tearing. The first insulating coating 320 has electrical insulation properties, which can separate the battery cell 200 and the casing 100, effectively preventing short circuits between the positive and negative electrodes inside the battery, thereby improving the safety and stability of the battery.

[0062] The first insulating coating 320 has a plurality of first openings. The porosity of the first insulating coating 320 is P, wherein P satisfies: 40% ≤ P ≤ 60%.

[0063] For example, a plurality of first openings are provided on the first insulating coating 320. The plurality of first openings form a porous structure. The plurality of first openings are evenly distributed on the first insulating coating 320. When the insulating film 300 covers the outer periphery of the battery cell 200, the first insulating coating 320 and the battery cell 200 are in direct contact.

[0064] During the electrolyte injection process, a portion of the electrolyte permeates into the positive electrode, negative electrode, and separator of the cell 200. This electrolyte is required for normal battery operation. Because the first insulating coating 320 has a first opening, some electrolyte can also flow into this opening, which is used to store a portion of the electrolyte. Thus, besides the space normally used for electrolyte storage in the battery, the insulating film 300 provides additional space for electrolyte storage, increasing the electrolyte retention capacity of the battery.

[0065] The electrolyte retention capacity in a battery is related to its performance. Sufficient electrolyte ensures that lithium ions can migrate smoothly between electrodes, reducing ion conduction resistance. This stable ion conduction helps maintain the battery's output power and efficiency. Furthermore, sufficient electrolyte ensures uniform chemical reactions on the electrode material surfaces, reducing uneven reactions or side reactions caused by insufficient electrolyte. The additional electrolyte stored in the insulating film 300 improves the stability of ion conduction and electrochemical reactions within the battery, thereby enhancing overall battery stability.

[0066] An increase in electrolyte retention means that the battery can maintain more stable performance during multiple charge-discharge cycles.

[0067] In addition, the design of the first opening helps dissipate heat and reduces the risk of heat accumulation in the battery under high load or rapid charging and discharging.

[0068] For example, porosity refers to the proportion of pore volume to the total volume in a material. Higher porosity means that there are more voids in the material, which can hold more electrolyte.

[0069] For example, the porosity P of the first insulating coating 320 satisfies: 40% ≤ P ≤ 60%. Conversely, when the porosity P < 40%, the lower porosity means that there is less space in the first insulating coating 320 to accommodate the electrolyte, which reduces the electrolyte retention in the battery and thus affects the lithium-ion conductivity. Insufficient electrolyte leads to obstructed ion transport paths, increases the battery's internal resistance, reduces charge and discharge efficiency, and consequently affects the overall performance and cycle life of the battery.

[0070] Conversely, when the porosity P > 60%, the higher porosity means a reduction in the solid portion of the first insulating coating 320, leading to a decrease in mechanical strength. This increases the risk of cracking or deformation of the first insulating coating 320. Excessively high porosity may cause structural instability in the first insulating coating 320, affecting the long-term reliability of the battery.

[0071] Therefore, in this embodiment, the porosity P satisfies: 40% ≤ P ≤ 60%. The first insulating coating 320 can provide sufficient space to store the electrolyte, ensuring effective lithium-ion conduction. Simultaneously, when the porosity of the first insulating coating 320 is within this range, the first insulating coating 320 possesses a certain mechanical strength, preventing damage and deformation of the first insulating coating 320.

[0072] Optionally, the porosity P of the first insulating coating 320 satisfies: 40% ≤ P ≤ 50%. Alternatively, the porosity P of the first insulating coating 320 satisfies: 50% ≤ P ≤ 60%. Alternatively, the porosity P of the first insulating coating 320 satisfies: 45% ≤ P ≤ 55%. Or, the porosity P of the first insulating coating 320 can be 42%, 47%, 52%, or 57%.

[0073] In one feasible implementation, the base layer 310 includes one or more of the following base layer components: polyethylene, polypropylene, and polyethylene terephthalate. When the base layer 310 includes multiple base layer components, the mass of each base layer component is equal.

[0074] In some embodiments, the base layer 310 may be polyethylene.

[0075] In other embodiments, the base layer 310 may be polypropylene.

[0076] In some other embodiments, the base layer 310 may be polyethylene terephthalate.

[0077] In some other embodiments, the base layer 310 may be a mixture of polyethylene and polypropylene, wherein the polyethylene and polypropylene are of equal mass.

[0078] In some other embodiments, the base layer 310 may be a mixture of polyethylene and polyethylene terephthalate, wherein the polyethylene and polyethylene terephthalate are of equal mass.

[0079] Polyethylene is chemically inert and can resist the attack of a variety of chemicals.

[0080] Polypropylene possesses mechanical strength and abrasion resistance. It is also resistant to chemicals such as acids and alkalis.

[0081] Polyethylene terephthalate (PET) possesses mechanical strength and rigidity. PET retains its physical properties at relatively high temperatures.

[0082] Polyethylene, polypropylene, and polyethylene terephthalate all possess good chemical inertness and are resistant to many chemicals, such as acids, alkalis, and solvents. Thus, the base layer 310 is chemically inert, enabling it to resist the erosion of electrolytes and other chemicals, ensuring long-term insulation performance, fulfilling its physical barrier function, preventing direct contact between the battery cell 200 and the aluminum casing, and avoiding wear and damage caused by friction or vibration.

[0083] For example, when base layer 310 comprises multiple base layer components, the masses of each component are equal. Thus, during the preparation of base layer 310, since the mass of each component is equal, the operator only needs to weigh the same mass. This simplifies the weighing process, reduces the possibility of errors, and improves operational convenience. Uniform quality requirements reduce complex calculations and adjustments, making the entire preparation process more efficient. Operators can complete material preparation faster, thereby accelerating production.

[0084] Conversely, when the base layer 310 includes multiple components, the masses of these components are not equal. This requires operators to weigh each component according to different proportions, increasing the complexity of the weighing process. Handling different masses and proportions makes the operation more cumbersome, increasing the operator's workload and reducing convenience.

[0085] As one feasible implementation method, refer to Figure 7 The thickness of the base layer 310 is B, and B satisfies: 80μm≤B≤90μm.

[0086] The thickness B of the base layer 310 provided in this application embodiment satisfies: 80μm≤B≤90μm. Conversely, when the thickness B of the base layer 310 is <80μm, the thinner base layer 310 may not provide sufficient strength, making the base layer 310 prone to damage during use. At the same time, the electrical and thermal insulation properties of the thinner base layer 310 may be insufficient, increasing the failure risk of the insulating film 300.

[0087] Conversely, when the thickness B of the base layer 310 is greater than 90 μm, the thicker base layer 310 increases the overall weight, which is not conducive to lightweight design. In addition, the thicker base layer 310 increases the thickness of the insulating film 300, thereby increasing the thickness of the battery and reducing the battery assembly effect.

[0088] Therefore, the thickness B of the base layer 310 provided in this embodiment satisfies: 80μm ≤ B ≤ 90μm. Within this thickness range, the base layer 310 can generally provide sufficient mechanical strength to resist external pressure and stress, ensuring structural stability. The base layer 310 within this thickness range can provide effective electrical insulation performance, preventing current leakage. A moderate thickness helps achieve good thermal management, providing a certain degree of thermal insulation without causing excessive heat accumulation. Furthermore, excessive thickness of the insulating film 300 is avoided, as it would affect the battery assembly effect.

[0089] Optionally, the thickness B of the base layer 310 satisfies: 80μm≤B≤85μm. Alternatively, the thickness B of the base layer 310 satisfies: 85μm≤B≤90μm. Or, the thickness B of the base layer 310 can be 82μm, 83μm, or 84μm.

[0090] In one feasible implementation, the base layer 310 includes a first surface located on one side in the thickness direction. A first insulating coating 320 is applied to the first surface. The first surface is adapted to face the battery cell 200. The first surface of the base layer 310 is the surface directly facing the battery cell 200. When the insulating film 300 is provided, its first surface faces the battery cell 200. This means that the main function of the insulating film 300 is to protect the cell 200 and prevent electrical short circuits between the cell 200 and the casing 100.

[0091] In some embodiments, refer to Figure 7 and Figure 8 The first insulating coating 320 completely covers the first surface of the substrate 310. When the first insulating coating 320 completely covers the substrate 310, its porous structure serves to store the electrolyte. By completely covering the first surface of the substrate 310, the first insulating coating 320 can maximize the electrolyte retention, which helps improve the ion conduction efficiency of the battery. Simultaneously, the first insulating coating 320, completely covering the substrate 310, provides mechanical protection for the substrate 310.

[0092] For example, the first insulating coating 320 can be a ceramic coating. The high hardness and wear resistance of ceramic materials can effectively prevent physical damage to the insulating film 300, such as scratches, abrasions and impacts, improve the structural stability of the insulating film 300, and thus extend the service life of the battery.

[0093] In other embodiments, the first insulating coating 320 covers a portion of the first surface of the base layer 310. This design, where the first insulating coating 320 partially covers the base layer 310, allows the insulating film 300 to adjust the coverage area of ​​the first insulating coating 320 according to specific application requirements, achieving greater design flexibility. For example, the first insulating coating 320 can be increased in high-stress or high-wear areas and decreased in other areas.

[0094] In one feasible implementation, the first insulating coating 320 is made by mixing inorganic particles, a binder, and a dispersant. The mass ratio of the inorganic particles to the binder is M; M satisfies: 0.8 ≤ M ≤ 1.2.

[0095] The mass ratio of inorganic particles to dispersant is N, where N satisfies: 12.5 ≤ N ≤ 30. The mass ratio of binder to dispersant is O, where O satisfies: 12.5 ≤ O ≤ 30.

[0096] The mass ratio M of inorganic particles to binder satisfies the condition: 0.8 ≤ M ≤ 1.2. Within this range, the ratio of inorganic particles to binder is relatively balanced, ensuring that the first insulating coating 320 has good mechanical strength and electrical insulation properties. Conversely, when M < 0.8, the inorganic particle content is too low, which may lead to a decrease in the insulation performance of the first insulating coating 320, while too much binder may cause the coating to be too soft. When M > 1.2, the inorganic particle content is too high, which may lead to increased brittleness and decreased adhesion of the first insulating coating 320, making it prone to peeling or cracking.

[0097] The mass ratio N of inorganic particles to dispersant satisfies: 12.5 ≤ N ≤ 30. Within this range, the amount of dispersant is sufficient to ensure the uniform distribution of inorganic particles in the adhesive and prevent particle agglomeration. When N > 30, insufficient dispersant may lead to agglomeration of inorganic particles, affecting the uniformity of the first insulating coating 320. When N < 12.5, excessive dispersant may affect the mechanical properties and adhesion of the first insulating coating 320, causing the first insulating coating 320 to become unstable.

[0098] The mass ratio of adhesive to dispersant, O, satisfies the following condition: 12.5 ≤ O ≤ 30. Within this range, the ratio of adhesive to dispersant contributes to the adhesion of the first insulating coating 320 and the uniform distribution of inorganic particles. When O < 12.5, insufficient adhesive may lead to decreased adhesion and insufficient mechanical strength of the first insulating coating 320. When O > 30, excessive adhesive may lead to insufficient dispersant, affecting the uniform distribution of inorganic particles and resulting in an uneven first insulating coating 320.

[0099] For example, inorganic particles are the main functional component of the first insulating coating 320. These inorganic particles typically possess high hardness and wear resistance, significantly improving the wear resistance of the first insulating coating 320 and extending its service life. An adhesive is used to bind the inorganic particles together and adhere the first insulating coating 320 to the base layer 310. A dispersant is used to improve the dispersibility of the inorganic particles in the adhesive, ensuring the uniformity and stability of the first insulating coating 320.

[0100] As one feasible implementation, the inorganic particles include one or more of the following inorganic particle components: hafnium dioxide, silicon dioxide, tin dioxide, cerium dioxide, magnesium oxide, nickel oxide, calcium oxide, zinc oxide, aluminum oxide, zirconium dioxide, aluminum oxide, silicon carbide, and boehmite.

[0101] When inorganic particles include multiple inorganic particle components, the masses of each inorganic particle component are equal.

[0102] In some embodiments, the inorganic particles may be any one of hafnium dioxide, silicon dioxide, tin dioxide, cerium dioxide, magnesium oxide, nickel oxide, calcium oxide, zinc oxide, aluminum oxide, zirconium dioxide, aluminum oxide, silicon carbide, and boehmite.

[0103] In other embodiments, the inorganic particles may be a mixture of at least two of hafnium dioxide, silicon dioxide, tin dioxide, cerium dioxide, magnesium oxide, nickel oxide, calcium oxide, zinc oxide, aluminum oxide, zirconium dioxide, aluminum oxide, silicon carbide, and boehmite.

[0104] For example, when the inorganic particles include hafnium dioxide, silicon dioxide, and tin dioxide, the masses of hafnium dioxide, silicon dioxide, and tin dioxide are equal.

[0105] Among them, hafnium dioxide, silicon dioxide, tin dioxide, cerium dioxide, magnesium oxide, nickel oxide, calcium oxide, zinc oxide, aluminum oxide, zirconium dioxide, aluminum oxide, silicon carbide, and boehmite can be nanoparticles.

[0106] For example, when inorganic particles comprise multiple inorganic particle components, the masses of each component are equal. Thus, during the preparation of inorganic particles, since the mass of each component is equal, the operator only needs to weigh the same mass. This simplifies the weighing process, reduces the possibility of errors, and improves operational convenience. Uniform quality requirements reduce complex calculations and adjustments, making the entire preparation process more efficient. Operators can complete material preparation faster, thereby accelerating production.

[0107] Conversely, when inorganic particles comprise multiple inorganic particle components, the masses of these components are unequal. This necessitates operators weighing each component according to different proportions, increasing the complexity of the weighing process. Handling varying masses and proportions makes the operation more cumbersome, increasing the operator's workload and reducing convenience.

[0108] The aforementioned inorganic particles have electrical insulation properties, which can improve the electrical insulation properties of the first insulating coating 320 and help the first insulating coating 320 separate the battery cell 200 and the aluminum shell.

[0109] As one possible implementation, the adhesive includes one or more of the following adhesive components: polyvinylidene fluoride, polyacrylate, polyvinyl alcohol, polyacrylic acid, and polyimide.

[0110] When the adhesive comprises multiple adhesive components, the mass of each adhesive component is equal.

[0111] In some embodiments, the adhesive may be any one of polyvinylidene fluoride, polyacrylate, polyvinyl alcohol, polyacrylic acid, and polyimide.

[0112] In other embodiments, the adhesive is a mixture of at least two of polyvinylidene fluoride, polyacrylate, polyvinyl alcohol, polyacrylic acid, and polyimide.

[0113] For example, when the adhesive includes polyvinylidene fluoride, polyacrylate, and polyvinyl alcohol, the mass of polyvinylidene fluoride, polyacrylate, and polyvinyl alcohol are equal.

[0114] For example, when an adhesive comprises multiple adhesive components, the masses of each component are equal. Thus, during adhesive preparation, since each component has an equal mass, the operator only needs to weigh the same mass. This simplifies the weighing process, reduces the possibility of errors, and improves operational convenience. Uniform quality requirements reduce complex calculations and adjustments, making the entire preparation process more efficient. Operators can complete material preparation faster, thereby accelerating production.

[0115] Conversely, when an adhesive comprises multiple components, the masses of these components are not equal. This necessitates operators weighing each component according to different proportions, increasing the complexity of the weighing process. Handling varying masses and proportions makes the operation more cumbersome, increasing the operator's workload and reducing convenience.

[0116] As one possible implementation, the dispersant includes one or more of the following dispersant components: sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, triethyl phosphate, polyacrylic acid, and sodium polyacrylate.

[0117] When the dispersant includes multiple dispersant components, the masses of each dispersant component are equal.

[0118] In some embodiments, the dispersant may be any one of sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, triethyl phosphate, polyacrylic acid, and sodium polyacrylate.

[0119] In other embodiments, the dispersant may be a mixture of at least two of sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, hydroxyethyl cellulose, triethyl phosphate, polyacrylic acid, and sodium polyacrylate.

[0120] For example, when the dispersant includes sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, the mass of sodium carboxymethyl cellulose, ethyl cellulose, methyl cellulose, and hydroxyethyl cellulose is equal.

[0121] For example, when a dispersant comprises multiple dispersant components, the masses of each component are equal. Thus, during dispersant preparation, since each dispersant component has an equal mass, the operator only needs to weigh the same mass. This simplifies the weighing process, reduces the possibility of errors, and improves operational convenience. Uniform quality requirements reduce complex calculations and adjustments, making the entire preparation process more efficient. Operators can complete material preparation faster, thereby accelerating production.

[0122] Conversely, when a dispersant comprises multiple components, the masses of these components are not equal. This necessitates operators weighing each component according to different proportions, increasing the complexity of the weighing process. Handling varying masses and proportions makes the operation more cumbersome, increasing the operator's workload and reducing convenience.

[0123] As one feasible implementation, the thickness of the first insulating coating 320 is H1, where H1 satisfies: 3μm≤H1≤5μm.

[0124] The thickness H1 of the first insulating coating 320 provided in this embodiment satisfies: 3μm ≤ H1 ≤ 5μm. Conversely, when the thickness H1 of the first insulating coating 320 is < 3μm, a thinner first insulating coating 320 may result in a reduced number of first openings. This is because in a thinner first insulating coating 320, the formation of a sufficient number and size of pores may be limited, thereby reducing the overall porosity. The reduction in porosity directly affects the liquid retention capacity of the first insulating coating 320.

[0125] The first opening is a key structural feature of the insulating film 300 for storing electrolyte. Fewer first openings mean less electrolyte storage. Since the electrolyte is the medium for ion conduction, reduced electrolyte storage will negatively impact battery performance. Insufficient electrolyte retention will lead to faster battery capacity decay, increased internal resistance, and reduced power output, thus decreasing battery cycle performance.

[0126] Conversely, when the thickness H1 of the first insulating coating 320 is greater than 5 μm, an excessively thick first insulating coating 320 may lead to thermal expansion mismatch, increasing the stress between the first insulating coating 320 and the base layer 310, thereby causing the first insulating coating 320 to crack or peel off. At the same time, an excessively thick first insulating coating 320 will result in material waste and increase production costs. Furthermore, an excessively thick first insulating coating 320 will increase the thickness of the battery, which is detrimental to battery assembly.

[0127] Therefore, in this embodiment, the thickness H1 of the first insulating coating 320 satisfies: 3μm≤H1≤5μm. This ensures the liquid retention capacity of the first insulating coating 320 while preventing cracking between the first insulating coating 320 and the base layer 310, thus ensuring the assembly effect of the battery.

[0128] Optionally, the thickness H1 of the first insulating coating 320 satisfies: 3μm ≤ H1 ≤ 4μm. Alternatively, the thickness H1 of the first insulating coating 320 satisfies: 4μm ≤ H1 ≤ 5μm. Alternatively, the thickness H1 of the first insulating coating 320 satisfies: 3.5μm ≤ H1 ≤ 4.5μm. Or, the thickness H1 of the first insulating coating 320 can be 3.3μm, 3.6μm, or 3.9μm.

[0129] As one feasible implementation, the aperture of the first opening is D, where D satisfies: 0.5μm≤D≤1.5μm.

[0130] In some embodiments of this application, the pore size D of the first opening satisfies: 0.5 μm ≤ D ≤ 1.5 μm. Conversely, when the pore size D of the first opening is < 0.5 μm, the first opening is too small. Since the liquid experiences greater friction and viscosity when passing through a narrow channel, a smaller first pore size increases the resistance to electrolyte flow, reduces the electrolyte flow rate, prevents the electrolyte from penetrating into the electrode material, impairs the ion conduction pathway, and consequently affects the battery's performance. Furthermore, an excessively small first opening may result in insufficient electrolyte storage, failing to meet the battery's needs during charging and discharging.

[0131] Conversely, when the aperture D of the first opening is greater than 1.5 μm, the larger first opening means that the solid portion of the first insulating coating 320 is reduced, resulting in a decrease in the mechanical strength of the first insulating coating 320 and an increase in its brittleness. This reduces the mechanical strength of the first insulating coating 320, and the first insulating coating 320 may be damaged during the manufacturing, assembly, or use of the battery, thus reducing the battery's performance.

[0132] Therefore, in this embodiment, D satisfies: 0.5μm ≤ D ≤ 1.5μm. This allows the first insulating coating 320 to provide sufficient mechanical strength, preventing damage to the insulating film 300 during use and maintaining the structural integrity of the battery. Simultaneously, when the pore size of the first opening is within this range, excessive friction and viscosity of the electrolyte within the first opening can be avoided, improving the fluidity of the electrolyte.

[0133] Optionally, the aperture D of the first opening satisfies: 0.5μm ≤ D ≤ 1.0μm. Alternatively, the aperture D of the first opening satisfies: 1.0μm ≤ D ≤ 1.5μm. Alternatively, the aperture D of the first opening satisfies: 0.7μm ≤ D ≤ 1.2μm. Or, the aperture D of the first opening can be 0.8μm, 0.9μm, 1.0μm, or 1.1μm.

[0134] As one feasible implementation method, refer to Figure 9 The insulating film 300 also includes a second insulating coating 330. The second insulating coating 330 is applied to the side of the first insulating coating 320 facing away from the substrate 310. The second insulating coating 330 has a second opening.

[0135] By providing a second insulating coating 330 on the side of the first insulating coating 320 facing away from the base layer 310, and by providing a second opening on the second insulating coating 330, the second insulating coating 330 can also be used to store electrolyte, further increasing the amount of electrolyte stored in the insulating film 300, thereby improving the battery's performance. In addition, the second insulating coating 330 can provide additional mechanical protection to prevent the battery from being damaged by physical impact or vibration.

[0136] As one feasible implementation, the thickness of the second insulating coating 330 is H2, where H2 satisfies: 1μm≤H2≤2μm.

[0137] In some embodiments of this application, the thickness H2 of the second insulating coating 330 satisfies: 1μm ≤ H2 ≤ 2μm. Conversely, when the thickness H2 of the second insulating coating 330 is < 1μm, the second insulating coating 330 is too thin, which is detrimental to its formation. Furthermore, an excessively thin second insulating coating 330 may not be uniformly coated on the surface of the first insulating coating 320, reducing the uniformity of the second insulating coating 330 and consequently affecting the uniform distribution of the electrolyte, which is detrimental to improving battery performance.

[0138] Conversely, when the thickness H2 of the second insulating coating 330 is greater than 2 μm, a thicker second insulating coating 330 may lead to heat accumulation and increase the risk of overheating. At the same time, a thicker second insulating coating 330 will increase the thickness of the insulating film 300, affecting the assembly of the insulating film 300 and the cell 200, thereby reducing the assembly effect of the battery.

[0139] Therefore, in this embodiment, the thickness H2 of the second insulating coating 330 satisfies: 1μm≤H2≤2μm. This improves the uniformity of the second insulating coating 330, ensures uniform distribution and effective storage of the electrolyte, and avoids the problem of excessive thickness and overheating of the insulating film 300 caused by an excessively thick second insulating coating 330.

[0140] Optionally, the thickness H2 of the second insulating coating 330 satisfies: 1μm ≤ H2 ≤ 1.5μm. Alternatively, the thickness H2 of the second insulating coating 330 satisfies: 1.5μm ≤ H2 ≤ 2μm. Or, the thickness H2 of the second insulating coating 330 can be 1.1μm, 1.2μm, or 1.3μm.

[0141] As one possible implementation, the second insulating coating 330 includes one or more of the following insulating components: polyvinylidene fluoride, polyacrylate, styrene-butadiene latex, and polyimide.

[0142] When the second insulating coating 330 includes multiple insulating components, the mass of each insulating component is equal.

[0143] In some embodiments, the second insulating coating 330 may be polyvinylidene fluoride.

[0144] In other embodiments, the second insulating coating 330 may be polyacrylate.

[0145] In some other embodiments, the second insulating coating 330 may be styrene-butadiene latex.

[0146] In some other embodiments, the second insulating coating 330 may be polyimide.

[0147] In some other embodiments, the second insulating coating 330 may be polyvinylidene fluoride (PVDF) or polyacrylate, wherein the mass of PVDF and polyacrylate is equal.

[0148] Polyvinylidene fluoride, polyacrylate, styrene-butadiene latex, and polyimide are materials that typically have electrical insulation properties and are suitable for electrical insulation applications.

[0149] For example, when the second insulating coating 330 comprises multiple insulating components, the masses of each insulating component are equal. Thus, when preparing the second insulating coating 330, since the mass of each insulating component is equal, the operator only needs to weigh the same mass. This simplifies the weighing process, reduces the possibility of errors, and improves operational convenience. Uniform quality requirements reduce complex calculations and adjustments, making the entire preparation process more efficient. Operators can complete material preparation faster, thereby accelerating production.

[0150] Conversely, when the second insulating coating 330 comprises multiple insulating components, the masses of these components are unequal. This necessitates that operators weigh each insulating component according to different proportions, increasing the complexity of the weighing process. Handling varying masses and proportions makes the operation more cumbersome, increases the operator's workload, and reduces convenience.

[0151] The first insulating coating 320 comprises high-hardness inorganic particles, providing excellent abrasion resistance and mechanical protection. The first insulating coating 320 primarily provides mechanical protection, thermal stability, and electrical insulation, while also locally storing electrolyte through a first open-cell structure. The second insulating coating 330 exhibits flexibility and adhesion. The second insulating coating 330 focuses on providing flexibility and adhesion, while the second open-cell structure further provides space for electrolyte storage.

[0152] The following explanation is based on the battery test results.

[0153] The battery is a square aluminum-cased lithium battery. The battery includes a cell 200 and an insulating film 300. In embodiment 1, the insulating film 300 includes a base layer 310 and a first insulating coating 320. In embodiment 2, the insulating film 300 includes a base layer 310, a first insulating coating 320, and a second insulating coating 330. In embodiment 3, the insulating film 300 only includes the base layer 310.

[0154] Taking a 200-cell, 80Ah, square aluminum-cased lithium battery with different electrolyte retention methods as an example, the electrolyte retention amount is recorded. Here, the electrolyte retention amount is equal to the difference between the finished weight of the single battery cell and the weight of the battery before electrolyte injection.

[0155] Batteries from different designs were subjected to charge-discharge cycles at a constant temperature of 25°C. They were charged at a constant current rate of 0.5C to the termination voltage of 3.8V, then switched to constant voltage charging with a cutoff current of 0.05C, and left to rest for 30 minutes. Then, they were discharged at a constant current rate of 0.5C to 2.0V. This charge-discharge cycle was repeated 2000 times. The discharge capacity of the 2000th cycle was recorded. The capacity retention rate after the cycle (%) was calculated as: discharge capacity after 2000 cycles / initial discharge capacity × 100%.

[0156] Based on the experimental results, refer to Figure 10 The results showed that the battery in Scheme 1 retained 86.07% of its capacity after 2000 cycles under the above experimental conditions, the battery in Scheme 2 retained 86.80% of its capacity after 2000 cycles, and the battery in Scheme 3, which uses an insulating film consisting only of the base layer 310, retained 83.66% of its capacity after 2000 cycles. The capacity retention rate of the battery in Scheme 2 after 2000 cycles is 3.14% higher than that of the battery in Scheme 3 after 2000 cycles.

[0157] Table 1 Electrolyte retention capacity of the battery

[0158]

[0159] Table 2. Results of Cyclic Analysis of Different Schemes in a 25℃ Constant Temperature Chamber

[0160]

[0161] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0162] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An insulating film (300), characterized in that, For use in a battery, the insulating film (300) comprises: Grassroots (310); A first insulating coating (320) is applied to at least one side surface of the base layer (310); The first insulating coating (320) has a plurality of first openings; the porosity of the first insulating coating (320) is P, wherein P satisfies: 40% ≤ P ≤ 60%.

2. The insulating film (300) according to claim 1, characterized in that, The aperture of the first opening is D, and D satisfies: 0.5μm≤D≤1.5μm.

3. The insulating film (300) according to claim 1, characterized in that, The thickness of the first insulating coating (320) is H1, and H1 satisfies: 3μm≤H1≤5μm.

4. The insulating film (300) according to claim 1, characterized in that, The base layer (310) includes a first surface located on one side in the thickness direction, the first insulating coating (320) is applied to the first surface, and the first surface is adapted to face the cell (200) of the battery.

5. The insulating film (300) according to claim 1, characterized in that, The thickness of the base layer (310) is B, and B satisfies: 80μm≤B≤90μm.

6. The insulating film (300) according to any one of claims 1-5, characterized in that, The insulating film (300) further includes a second insulating coating (330), which is applied to the side of the first insulating coating (320) away from the base layer (310); the second insulating coating (330) has a second opening.

7. The insulating film (300) according to claim 6, characterized in that, The thickness of the second insulating coating (330) is H2, wherein H2 satisfies: 1μm≤H2≤2μm.

8. The insulating film (300) according to any one of claims 1-5, characterized in that, The base layer (310) includes one of the following base layer components: polyethylene, polypropylene, and polyethylene terephthalate.

9. The insulating film (300) according to claim 6, characterized in that, The second insulating coating (330) includes one of the following insulating components: polyvinylidene fluoride, polyacrylate, styrene-butadiene latex, and polyimide.

10. A battery, characterized in that, It includes a battery cell (200) and an insulating film (300) as described in any one of claims 1-9, wherein the insulating film (300) covers the battery cell (200).

11. The battery according to claim 10, characterized in that, The first insulating coating (320) of the insulating film (300) abuts against the battery cell (200).

12. The battery according to claim 11, characterized in that, The insulating film (300) further includes a second insulating coating (330), which is applied to the side of the first insulating coating (320) away from the base layer (310) of the insulating film (300); the second insulating coating (330) has a second opening, and the second insulating coating (330) abuts against the battery cell (200).

13. A battery device, characterized in that, Includes the battery according to any one of claims 10-12.

14. An electrical appliance, characterized in that, Includes the battery according to any one of claims 10-12 or the battery device according to claim 13.

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