Battery, electric device, filler structure, and preparation method for filler structure

Abstract

The present application discloses a battery, an electric device, a filler structure, and a preparation method for a filler structure. The battery comprises a case, and further comprises the filler structure. The filler structure is arranged in at least one of a space between the case and an electrode core, and the interior of the electrode core; and the filler structure comprises a skeleton matrix and an adaptive material arranged on the skeleton matrix, the skeleton matrix supports the adaptive material, and the adaptive material can expand upon absorbing an electrolyte solution so as to generate a constraint force on the electrode core.

Description

Batteries, electrical devices, fillers, and methods for preparing fillers

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411997713.X, filed on December 31, 2024, entitled "Battery, Electrical Device, Filler and Method for Preparing Filler", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, specifically to batteries, electrical devices, fillers, and methods for preparing fillers. Background Technology

[0004] During the charging and discharging process, the electrode core expands. If no restraint is applied to the electrode core, it will lead to failure of the internal interface bonding, deterioration, and increased impedance, thereby affecting the cycle performance of the battery. Summary of the Invention

[0005] This application aims to at least partially solve one of the technical problems in the related art. To this end, one object of this application is to provide a battery, an electrical device, a filler, and a method for preparing the filler. The battery of this application, by providing a filler in the casing to apply a restraining force to the electrode core, can adaptively apply the restraining force according to changes in the electrode core volume, thereby improving the cycle performance of the battery.

[0006] In a first aspect, this application provides a battery, including a casing, an electrode core housed within the casing, and a filler;

[0007] The filler is located at least one of the following: between the shell and the pole core, and inside the pole core;

[0008] The filler includes a skeleton matrix and an adaptive material disposed on the skeleton matrix. The skeleton matrix supports the adaptive material, which can expand after absorbing electrolyte to generate a restraining force on the electrode core.

[0009] In this application, the framework matrix serves to support the adaptive material;

[0010] After the filler comes into contact with the electrolyte, the electrolyte enters the adaptive material, causing the adaptive material to expand in volume and exert a compressive restraining force on the electrode core. The presence of the framework matrix serves two purposes: firstly, it supports the adaptive material, and secondly, it further ensures the restraining force of the filler on the electrode core. Therefore, by utilizing the expansion effect of the adaptive material and the supporting effect of the framework matrix, a restraining force can be formed on the electrode core by the filler, improving the cycle performance of the battery.

[0011] In some implementations, at least one of the following (I) to (III) is satisfied:

[0012] (I) The framework matrix is ​​a porous network structure, and at least part of the adaptive material is dispersed in the porous network structure of the framework matrix;

[0013] (II) The framework matrix can expand after absorbing electrolyte;

[0014] (III) The skeleton matrix has resilience.

[0015] In some embodiments, the framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

[0016] In some implementations, the battery satisfies at least one of the following (i) and (ii):

[0017] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0018] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0019] In some embodiments, the mass ratio of the adaptive material to the skeleton matrix in the filler is 6:4 to 9:1.

[0020] In some embodiments, the thickness of the filler after absorbing the electrolyte is 0.1% to 30% of the total thickness of the casing.

[0021] In some embodiments, the filler is disposed on a large surface corresponding to the pole core, satisfying at least one of the following (A) and (B):

[0022] (A) The filler is located between the large surface of the pole core and the shell;

[0023] (B) The filler is placed inside the electrode core at the position corresponding to the large surface of the electrode core.

[0024] In some embodiments, the filler is arranged corresponding to the large surface area of ​​the pole core, satisfying at least one of the following (a) and (b):

[0025] (a) The filler is located on the inner wall of the shell facing the large surface of the pole core;

[0026] (b) The filler is located on the outer surface of the large facet of the pole core.

[0027] In some embodiments, the filler is located in the empty foil on the outer surface of the large surface of the electrode core.

[0028] In some embodiments, the filler has a layered structure, and the orthographic projection area of ​​the filler in the thickness direction is 20% to 130% of the outer surface area of ​​the core.

[0029] In some embodiments, the electrode cores include multiple cores, and a filler is provided between two adjacent electrode cores.

[0030] In some embodiments, the shape of the filler when projected orthogonally in the thickness direction includes at least one of a rectangle, a triangle, a square, or an irregular shape.

[0031] In some implementations, the structure of the electrode core satisfies at least one of the following (a) and (b):

[0032] (a) The pole core includes one or a combination of two of the following: wound pole core and laminated pole core;

[0033] (b) The electrode core includes a positive electrode plate, a negative electrode plate and an isolation structure, the isolation structure being adapted to insulate the positive electrode plate and the negative electrode plate.

[0034] In some embodiments, the battery further includes an electrolyte that satisfies at least one of the following (①) and (②):

[0035] (①) The electrolyte is filled between the electrode core and the shell;

[0036] (②) The electrolyte is filled inside the electrode core.

[0037] Secondly, this application proposes an electrical device.

[0038] According to embodiments of this application, the electrical device includes the battery described in the first aspect. Therefore, the electrical device of this application has a good service life and safety performance.

[0039] Thirdly, this application proposes a filler comprising a skeleton matrix and an adaptive material disposed on the skeleton matrix, wherein the skeleton matrix is ​​adapted to support the adaptive material, and the adaptive material is capable of expanding after absorbing electrolyte.

[0040] The filler proposed in this application can be applied to batteries. The features and advantages described above with respect to the battery in the first aspect of this application also apply to the filler in the third aspect of this application, and will not be repeated here.

[0041] In some embodiments, the filler satisfies at least one of the following (I) to (III):

[0042] (I) The framework matrix is ​​a porous network structure, and at least part of the adaptive material is dispersed in the porous network structure of the framework matrix;

[0043] (II) The framework matrix can expand after absorbing electrolyte;

[0044] (III) The skeleton matrix has resilience.

[0045] In some embodiments, the framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

[0046] In some implementations, the filler satisfies at least one of the following (i) and (ii):

[0047] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0048] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0049] In some implementations, the mass ratio of the adaptive material to the framework matrix is ​​6:4 to 9:1.

[0050] Fourthly, this application proposes a method for preparing a filler, comprising:

[0051] The filler is obtained by mixing the material of the skeleton matrix with the adaptive material, wherein the adaptive material is disposed on the skeleton matrix, the skeleton matrix is ​​adapted to support the adaptive material, and the adaptive material can expand after absorbing the electrolyte.

[0052] The preparation method is convenient to operate and the process is relatively simple. The resulting filler can be used in batteries. The features and advantages described above for the battery in the first aspect of this application are also applicable to the method for preparing the filler in the fourth aspect of this application, and will not be repeated here.

[0053] In some embodiments, the mixing of the skeleton matrix material with the adaptive material includes: impregnating the skeleton matrix in a dispersion of the adaptive material to obtain an impregnated part, and hot-pressing the impregnated part to obtain a filler.

[0054] In some implementations, the method satisfies at least one of the following (i) and (ii):

[0055] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0056] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0057] In some embodiments, the dispersion satisfies at least one of the following:

[0058] (α) The dispersion is an emulsion;

[0059] (β) The dispersed phase of the dispersion includes an adaptive material, and the continuous phase includes at least one of water and an organic solvent;

[0060] (γ) Based on the total mass of the dispersion, the mass fraction of the dispersed phase in the dispersion is 5% to 80%.

[0061] In some embodiments, during the hot pressing step, at least one of the following (a) and (b) is satisfied;

[0062] (a) The hot pressing temperature is 40℃~130℃;

[0063] (B) The hot pressing pressure is 0.5MPa to 50MPa.

[0064] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0065] The above-described additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0066] Figure 1 shows a schematic diagram of the structure of a square battery according to some embodiments of this application.

[0067] Figure 2 shows a schematic cross-sectional view of a square battery in the thickness direction according to some embodiments of this application.

[0068] Figure 3 shows a schematic diagram of the structure of a cylindrical battery according to some embodiments of this application.

[0069] Figure 4 shows a schematic diagram of the radial cross-sectional structure of a cylindrical battery according to some embodiments of this application.

[0070] In Figures 1-4, the reference numerals represent: 1. Shell, 2. Electrode core, 3. Filling layer, 4. Square battery, and 5. Cylindrical battery.

[0071] Figure 5 shows a cross-sectional electron microscope image of the polypropylene diaphragm (PE) used in Example 1, where "PE" refers to the polypropylene diaphragm.

[0072] Figure 6 shows a cross-sectional electron microscope image of the filler prepared in Example 1; in the figure, "PE-based composite" refers to the filler prepared from the polypropylene diaphragm and styrene-butadiene rubber prepared in Example 1.

[0073] Figure 7 shows a comparison of the cycle performance test results of the batteries obtained in Examples 1, 2 and Comparative Example 1 of this application; in the figure, "Spec" refers to the target curve; "Experiment 1" refers to the battery prepared in Example 1; "Experiment 2" refers to the battery prepared in Example 2; "Control Group" refers to the battery prepared in Comparative Example 1; the horizontal axis represents the number of cycles and the vertical axis represents the cycle capacity retention rate. Detailed Implementation

[0074] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0075] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0076] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this application.

[0077] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0078] The restraint force on the battery core has a significant impact on battery performance. Gaps between the casing and the core can lead to unrestrained swelling of the core, interface adhesion failure and degradation, increased impedance, and poor cycle performance. However, due to battery structure limitations, it is difficult to directly influence the restraint force on the core. Currently, mechanical devices are often added to the outside of the battery casing to apply restraint forces, thereby adjusting the changes in the restraint force on the core during cycle expansion. However, while this method involves adding clamps to the outside of the battery and applying pressure stress to the casing to control the restraint force, it cannot directly apply a corresponding restraint force to the core. Furthermore, different casing materials, space utilization, and core structures all affect the external stress transmission, resulting in many uncontrollable factors. Therefore, there is an urgent need for a technology that can directly apply adaptive restraint forces to the battery core.

[0079] Therefore, the first aspect of the present application provides a battery, including a casing, an electrode core housed inside the casing, and a filler;

[0080] The filler is located at least one of the following: between the shell and the pole core, and inside the pole core;

[0081] The filler includes a skeleton matrix and an adaptive material disposed on the skeleton matrix. The skeleton matrix supports the adaptive material, which can expand after absorbing electrolyte to generate a restraining force on the electrode core.

[0082] In this application, the filler skeleton matrix and the adaptive material disposed on the skeleton matrix are used. The skeleton matrix supports the adaptive material, which expands after absorbing electrolyte to generate a restraining force on the electrode core. The phrase "skeleton matrix supports the adaptive material" indicates that the adaptive material can be on the surface of the skeleton matrix or inside the skeleton matrix. Furthermore, the distribution of the filler within the shell can be in three ways: 1) the filler is disposed between the shell and the electrode core; 2) the filler is disposed inside the electrode core, for example, between the positive electrode and the isolation structure, or between the negative electrode and the isolation structure, to directly apply an adaptive restraining force to the electrode; 3) a filler is disposed between the shell and the electrode core, and also inside the electrode core.

[0083] In this embodiment, the framework matrix serves to support the adaptive material. After the adaptive material comes into contact with the electrolyte, the solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption, and then gradually undergo volume expansion deformation. After being subjected to compression, it releases some electrolyte and undergoes volume contraction deformation.

[0084] After the filler comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption. The adaptive material expands in volume and is confined within the space between the shell and the electrode core, or within the electrode core itself, directly exerting a compressive restraining force on the electrode core. During normal charging and discharging of the battery, lithium insertion / extraction of charge carriers such as lithium ions causes changes in the internal stress of the electrode core, resulting in cyclic expansion / contraction. At this time, the filler absorbs / releases electrolyte under the compression of the electrode core, adaptively applying a restraining force to the electrode core. The presence of the framework matrix serves two purposes: supporting the adaptive material and further ensuring the restraining force of the filler on the electrode core. Therefore, by utilizing the expansion effect of the adaptive material and the supporting effect of the framework matrix, a restraining force of the filler on the electrode core can be formed, improving the cycle performance of the battery.

[0085] In addition, a filler is placed inside the casing. In the early stage of battery cycling, the filler absorbs free electrolyte and expands to fill the gaps, thus playing a restraining role. After the electrode core has undergone multiple cycles and its volume gradually expands, the filler is squeezed and gradually releases electrolyte, replenishing the electrolyte loss during multiple cycles and improving battery performance. Therefore, it has the dual benefits of improving electrode core restraint and slow electrolyte release.

[0086] In addition, the filler provided in this application embodiment can also be applied to the electrode core expansion caused by the formation and growth of the SEI film in the electrode, physical and electrochemical expansion, gas generation expansion, etc., so as to apply an adaptive restraining force to protect the battery safety.

[0087] The embodiments of this application are applicable to batteries of various conventional shapes. In the square battery 4 shown in Figures 1 and 2, the filling layer 3 is located between the casing 1 and the electrode core 2. In the cylindrical battery 5 shown in Figures 3 and 4, the filling layer 3 is located between the casing 1 and the electrode core 2.

[0088] In some embodiments of this application, the battery satisfies at least one of the following (I) to (III):

[0089] (I) The framework matrix is ​​a porous network structure, and at least part of the adaptive material is dispersed in the porous network structure of the framework matrix;

[0090] (II) The framework matrix can expand after absorbing electrolyte;

[0091] (III) The skeleton matrix has resilience.

[0092] The framework matrix has a porous network structure, which is beneficial for dispersing the adaptive material and can exhibit a certain degree of expansion. Both the "framework matrix" and the "adaptive material" have certain expansion characteristics. The "framework matrix" has relatively strong elasticity and can quickly recover its original shape after the external force is weakened or removed. The "adaptive material" has relatively strong creep. After the adaptive material comes into contact with the electrolyte, the solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption, and then gradually expand and deform.

[0093] After the filler comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption. The adaptive material expands in volume, and the framework matrix adapts to the volume change of the adaptive material, resulting in overall expansion of the filler, which can exert a compressive restraining force on the electrode core. During normal charging and discharging of the battery, lithium insertion and extraction of charge carriers such as lithium ions cause changes in the internal stress of the electrode core, resulting in cyclic expansion / contraction. At this time, the filler absorbs / releases electrolyte under the compression of the electrode core, adaptively applying a restraining force to the electrode core. Therefore, by utilizing the expansion effect of the "framework matrix" and the "adaptive material," as well as the synergistic effect of the resilience of the "framework matrix" and the swelling property of the "adaptive material," the restraining force of the filler on the electrode core and the adaptive adjustment capability of this restraining force can be improved, thereby improving the cycle performance of the battery.

[0094] The framework matrix can expand after absorbing electrolyte. On the one hand, the framework matrix can play a similar role to the restraining force of the electrode core as the adaptive material. On the other hand, it makes the framework matrix have a certain elasticity, which can adapt to the volume expansion or contraction changes of the adaptive material, and has resilience, thus improving the overall adaptive restraining force adjustment capability of the filler.

[0095] In some embodiments of this application, the framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

[0096] In this embodiment, the adaptive material has a particulate structure, which is beneficial for better dispersion in the porous network matrix. By utilizing the expansion effect of the "matrix matrix" and the "adaptive material", as well as the synergistic effect of the elasticity of the "matrix matrix" and the swelling property of the "adaptive material", the binding force of the filler on the electrode core and the adaptive adjustment capability of the binding force can be improved, thereby improving the cycle performance of the battery.

[0097] In some embodiments of this application, the battery satisfies at least one of the following (i) and (ii):

[0098] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0099] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0100] In this embodiment, the material of the skeleton matrix includes, but is not limited to, at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene. These materials are porous materials that can provide a three-dimensional mesh structure and exhibit good elasticity. Furthermore, they can disperse more adaptive material, utilizing their resilience to constrain the adaptive material and improve the overall adaptive restraint force of the filler on the electrode core. Simultaneously, these materials can absorb electrolyte and undergo adaptive expansion, and release electrolyte and undergo adaptive contraction, exhibiting good elasticity and creep resistance. As the electrode core expands / contracts, the electrode core exerts a squeezing effect on the filler, causing the adaptive material to absorb / release electrolyte, thus forming an adaptive restraint force on the electrode core.

[0101] In the embodiments of this application, the adaptive material includes, but is not limited to, at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber. These materials can absorb electrolyte and undergo adaptive expansion, and release electrolyte and undergo adaptive contraction. They have good elasticity and creep properties. As the core volume expands / contracts, the core exerts a squeezing effect on the filler, causing the adaptive material to absorb / release electrolyte and form an adaptive restraint force on the core.

[0102] In some embodiments of this application, the mass ratio of the adaptive material to the skeleton matrix in the filler is 6:4 to 9:1. The sum of the first and second terms of the mass ratio is 10.

[0103] In this embodiment, the mass ratio of the adaptive material to the skeleton matrix meets the above requirements. On the one hand, this helps to fully utilize the creep property of the adaptive material, and on the other hand, it enables the skeleton matrix to provide a certain rigid support and elasticity, thereby allowing the filler as a whole to directly form a good adaptive restraint force on the pole core.

[0104] As examples, the mass ratio of the adaptive material to the skeleton matrix is ​​6:4, 7:3, 8:2, 9:1, etc.

[0105] In some embodiments of this application, the thickness of the filler after absorbing electrolyte is 0.1% to 30% of the total thickness of the casing. Here, the thickness of the filler can be understood as the thickness of the filler at any state from the start of electrolyte absorption to absorption saturation. For example, the thickness of the filler when the adaptive material begins to absorb electrolyte is 0.1% to 30% of the total thickness of the casing. In the embodiments of this application, "total thickness of the casing" refers to the distance between two opposite sides in the thickness direction inside the casing. For example, in a square battery, it refers to the distance between two opposite sides in the thickness direction inside a cuboid casing; in a cylindrical battery, it refers to the inner diameter of the cylindrical casing. It can also be understood that the thickness of the filler after absorbing electrolyte and expanding is 0.1% to 30%. It can also be understood that the thickness of the filler after absorbing electrolyte and expanding until the filler reaches absorption saturation is 0.1% to 30% of the total thickness of the casing. Because the adaptive material in the filler expands after absorbing electrolyte, the overall thickness of the filler changes after absorbing electrolyte. Furthermore, the thickness of the filler after expansion is 0.5% to 10% of the total thickness within the shell.

[0106] In this embodiment, the thickness of the filler satisfies the above conditions. On the one hand, it is beneficial to effectively exert the adaptive restraining force of the filler on the electrode core; on the other hand, it is beneficial to maintain a high energy density of the battery and also to apply a restraining force to the electrode core that it can withstand without being damaged by compression.

[0107] As an example, different battery types and shapes have varying internal space utilization rates and different capacities occupied by the electrode core. Therefore, the thickness of the filler can be designed based on the different internal space utilization rates of the battery casing and the different restraint force requirements of the electrode core. For example, for pouch batteries: the casing and electrode core are tightly fitted, resulting in relatively low space utilization and a relatively small filler thickness. For rigid packaging such as steel or aluminum casings, there is a certain gap between the casing and electrode core, resulting in relatively high space utilization and a relatively large filler thickness.

[0108] As an example, the thickness of the filler after absorbing the electrolyte is 0.1%, 0.2%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, 5%, 5.2%, 5.4%, 5.6%, 5.8%, 6%, 6.2%, 6.4%, 6.6%, 6.8%, 7%, 7.2%, 7.4%, 7.6%, 7.8%, 7%, 8.2%, 8.4%, 8% of the total thickness of the shell. 0.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5%, 30%, etc.

[0109] As an example, the thickness of the filler after absorbing the electrolyte is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% of the total thickness inside the shell.

[0110] In some embodiments of this application, the filler is disposed on a large surface corresponding to the pole core, satisfying at least one of the following (A) and (B):

[0111] (A) The filler is located between the large surface of the pole core and the shell;

[0112] (B) The filler is placed inside the electrode core at the position corresponding to the large surface of the electrode core.

[0113] In this embodiment, "large surface of the electrode core" refers to the side surface of the outer ring of the electrode core with a relatively large area. This is because, during the charge-discharge cycle of the battery, the volume expansion / contraction of the electrode core is more noticeable on the side surface with a larger area, while it is less noticeable on some smaller side surfaces or end faces. Therefore, the filler is fixed to the large surface of the outer ring of the electrode core, or the inner side of the casing corresponding to the large surface. As an example, for a rectangular battery, the large surface of the outer ring of the electrode core refers to the plane in the length and width directions; for a cylindrical battery, the large surface of the outer ring of the electrode core refers to the outer surface of the entire cylindrical electrode core.

[0114] In some embodiments of this application, the filler is arranged corresponding to the large surface area of ​​the pole core, satisfying at least one of the following (a) and (b):

[0115] (a) The filler is located on the inner wall of the shell facing the large surface of the pole core;

[0116] (b) The filler is located on the outer surface of the large facet of the pole core.

[0117] In this embodiment, the filler can be fixed to the inner wall of the shell, which is convenient to operate, highly operable, and has little impact on the manufacturing process of the electrode core.

[0118] In this embodiment of the application, the filler can also be fixed on the outer surface of the large surface of the electrode core, that is, on the surface of the outer ring of the electrode core. In this case, the manufacturing process of the electrode core can be adjusted adaptively. For example, after the active film layer is coated on the current collector, the process of manufacturing the filler can be added.

[0119] In some embodiments of this application, the battery satisfies at least one of the following:

[0120] The filler also includes an adhesive layer and / or a thermo-pressed diffusion layer between itself and the inner wall of the shell;

[0121] The filler and the outer surface of the electrode core also include an adhesive layer and / or a hot-pressed diffusion layer.

[0122] In this embodiment, various methods can be selected to fix the filler to the inner wall of the housing or the outer surface of the electrode core. For example, the filler can be fixed to the inner wall of the housing or the outer surface of the electrode core using tape, or the filler can be directly fixed to the inner wall of the housing or the outer surface of the electrode core using a hot-pressing method.

[0123] In some embodiments of this application, the filler is disposed at the empty foil on the outer surface of the large surface of the electrode core.

[0124] "Empty foil" refers to the current collector of the electrode, which can be the current collector of the negative electrode or the current collector of the positive electrode.

[0125] When the filler is fixed on the outer surface of the large surface of the electrode core, the outer surface of the large surface of the electrode core can be fixed on the surface of the active film layer of the electrode (the active film layer on the current collector surface is coated on both sides), or it can be fixed on the current collector surface of the electrode (the active film layer on the current collector surface is coated on one side), that is, the "empty foil area".

[0126] In some embodiments of this application, the filler is a layered structure, and the orthographic projection area of ​​the filler in the thickness direction is 20% to 130% of the outer surface area of ​​the core large surface.

[0127] In this embodiment, "the outer surface area of ​​the large surface of the electrode core" refers to the area of ​​any relatively large side surface of the outer ring of the electrode core. This is because, during the charge-discharge cycle of the battery, the volume expansion / contraction of the electrode core is more noticeable on the side surface with a larger area, while it is less noticeable on some smaller side surfaces or end faces. Therefore, the filler is fixed at the large surface of the outer ring of the electrode core, or on the inner side of the shell corresponding to the large surface. "The orthogonal projection area of ​​the filler in the thickness direction" also refers to the orthogonal projection area of ​​the filler located at the large surface of the electrode core in the thickness direction. Here, the filler can be one layer or multiple layers. As an example, for a rectangular battery, the large surface of the outer ring of the electrode core refers to the plane in the length and width directions; for a cylindrical battery, the large surface of the outer ring of the electrode core refers to the outer surface of the entire cylindrical electrode core.

[0128] In this embodiment, the projected area of ​​the filler in the thickness direction satisfies the above conditions, which is beneficial for applying an effective adaptive restraint force to the electrode core and improving the cycle performance of the battery. Since the filler is located between the outer surface of the electrode core and the inner side of the shell, increasing the area of ​​the filler can form a state that fully wraps the outer surface of the electrode core. In this case, the total area of ​​the filler perpendicular to the thickness direction will be greater than the outer surface area of ​​the electrode core, which is beneficial for improving the restraint effect on the electrode core and forming an effective insulating layer.

[0129] As an example, the orthogonal projected area of ​​the filler in the thickness direction is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130% of the outer surface area of ​​the core.

[0130] In some embodiments of this application, the electrode core includes multiple cores, and a filler is provided between two adjacent electrode cores.

[0131] In this embodiment, the electrode core can be one, or a combination of two or more electrode cores. For a combination structure of two or more electrode cores, a filler is provided between two adjacent electrode cores. The filler absorbs or releases electrolyte and undergoes adaptive expansion or contraction, thereby forming a direct restraining force on the electrode core.

[0132] In some embodiments of this application, the shape of the filler when projected orthogonally in the thickness direction includes at least one of a rectangle, a triangle, a square, or an irregular shape.

[0133] In this application embodiment, the shape of the filler includes, but is not limited to, at least one of rectangle, triangle, square, and irregular shape. The shape of the filler can be adjusted based on factors such as the requirements of the battery core for the restraint strength and the shape of the battery.

[0134] In some embodiments of this application, the structure of the electrode core satisfies at least one of the following (a) and (b):

[0135] (a) The pole core includes one or a combination of two of the following: wound pole core and stacked pole core.

[0136] (b) The electrode core includes a positive electrode plate, a negative electrode plate, and an isolation structure; the isolation structure is adapted to insulate the positive electrode plate and the negative electrode plate from each other.

[0137] From the perspective of the forming process of the electrode core, the electrode core includes wound electrode core and stacked electrode core. The embodiments of this application are applicable to both wound electrode core and stacked electrode core, and can apply adaptive restraint force to the electrode core to improve the battery cycle performance.

[0138] In this embodiment, the electrode core includes a positive electrode sheet, a negative electrode sheet, and an isolation structure. Based on the positional relationship between the positive and negative electrode sheets, the positive electrode sheet can cover the negative electrode sheet, the negative electrode sheet can cover the positive electrode sheet, or the positive and negative electrode sheets can not cover each other, i.e., the conventional isolation state. This embodiment is applicable to all of these battery structures and can apply adaptive restraint force to the electrode core to improve the battery cycle performance.

[0139] Furthermore, in some embodiments, the isolation structure is a separator, and an adhesive layer is usually provided between the positive electrode and the separator, and between the negative electrode and the separator, to improve the connection stability between the positive electrode and the separator, and between the negative electrode and the separator. Filling the gap between the casing and the electrode core with a filler serves two purposes. First, in the early stages of battery cycling, the filler absorbs free electrolyte and expands to fill the gap, providing a restraining force while also preventing excessive swelling and interface degradation of the electrode core. This helps prevent excessive internal electrolyte from causing creep failure of the adhesive layer, resulting in a loose interface, decreased stability, and hindering battery performance improvement. Second, as the electrode core expands gradually after multiple cycles, the filler is compressed and gradually releases electrolyte, replenishing the electrolyte consumed during cycling. This achieves the dual benefits of improving electrode core restraint and slow electrolyte release.

[0140] In some embodiments of this application, the battery further includes an electrolyte that satisfies at least one of the following (①) and (②):

[0141] (①) The electrolyte is filled between the electrode core and the shell;

[0142] (②) The electrolyte is filled inside the electrode core.

[0143] In this embodiment, the electrolyte is filled between the electrode core and the shell, or the electrolyte is filled inside the electrode core, or the electrolyte is filled between the electrode core and the shell and inside the electrode core; thus, the filler is immersed in the electrolyte.

[0144] In some embodiments of this application, the electrolyte includes a solvent and an electrolyte salt.

[0145] Furthermore, the electrolyte salt includes electrolyte salts conventional in the art, such as lithium salts or sodium salts.

[0146] Furthermore, the solvent includes conventional electrolyte solvents in the art, such as water or organic solvents; the organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propionate, and ethyl propionate.

[0147] According to embodiments of this application, the battery includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During battery charging and discharging, active ions repeatedly insert and extract between the positive and negative electrode plates. The electrolyte acts as a conductor of ions between the positive and negative electrode plates. The separator is disposed between the positive and negative electrode plates, primarily to prevent short circuits between the positive and negative electrodes, while simultaneously allowing ions to pass through.

[0148] In some embodiments of this application, the positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side surface of the positive current collector, the positive active material layer including a positive active material.

[0149] For example, when the positive electrode sheet is used in a lithium-ion battery, the positive electrode active material can be any positive electrode active material known in the art for lithium-ion batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, 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 transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (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) or its modified compounds. Examples of lithium phosphates with an olivine structure 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 manganese iron phosphate, or lithium manganese iron phosphate and carbon composites.

[0150] In some embodiments of this application, the positive electrode current collector may include a metal foil or a composite positive electrode current collector. For example, the metal foil may be aluminum foil. The composite positive electrode current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. For example, the composite negative electrode current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0151] In some embodiments of this application, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0152] In some embodiments of this application, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0153] In some embodiments of this application, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet (e.g., positive electrode active material, conductive agent, binder) in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0154] In some embodiments of this application, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material.

[0155] In some embodiments of this application, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0156] In some embodiments of this application, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: graphite (including at least one of natural graphite and artificial graphite), soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include at least one of elemental tin, tin oxide compounds, and tin alloys.

[0157] In some embodiments of this application, the negative electrode active material layer may optionally include a binder. The binder may include at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0158] In some embodiments of this application, the negative electrode active material layer may optionally include a conductive agent. The conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0159] In some embodiments of this application, the negative electrode active material layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0160] In some embodiments of this application, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet (e.g., negative electrode active material, conductive agent, binder and any other components) in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0161] 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. According to embodiments of this application, the separator membrane material may include at least one of glass fiber, nonwoven fabric, polyvinylidene fluoride, polyethylene, polypropylene, or a composite material of polyethylene and polypropylene.

[0162] In some embodiments of this application, the battery may include an outer packaging. This outer packaging is used to encapsulate the positive electrode, the negative electrode, and the electrolyte.

[0163] In some embodiments of this application, the outer packaging may include a shell and a cover. The shell may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The shell has an opening communicating with the receiving cavity, and the cover plate can be placed over the opening to close the receiving cavity.

[0164] In some embodiments of this application, the outer packaging of the battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell.

[0165] The outer packaging of the battery can also be a soft pack, such as a pouch. The material of the soft pack can be aluminum-plastic film or plastic, such as plastic, which may include at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0166] The battery in this application embodiment can be a secondary battery such as a lithium-ion battery, a sodium-ion battery, a lithium metal battery, or a sodium metal battery.

[0167] The batteries in this application embodiment may be in the form of battery cells, battery modules, and battery packs. In some embodiments, battery cells may be assembled into battery modules, and the number of battery cells contained in a battery module may be one or more, the specific number of which can be selected by those skilled in the art based on the application and capacity of the battery module. In some embodiments, battery modules may also be assembled into battery packs, and the number of battery modules contained in a battery pack may be one or more, the specific number of which can be selected by those skilled in the art based on the application and capacity of the battery pack.

[0168] The second aspect of this application provides an electrical device including the battery proposed in the first aspect of this application.

[0169] According to embodiments of this application, the electrical device includes the battery described in the first aspect. Therefore, the electrical device of this application has a good service life and safety performance.

[0170] Battery cells, battery modules, and battery packs can be used as power sources for electrical devices or as energy storage units for electrical devices. Electrical devices can include, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0171] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0172] As one example, the electrical device can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the battery for this electrical device, a battery pack or battery module can be used.

[0173] Another example of the device could be a mobile phone, tablet computer, laptop computer, etc. This device typically requires a slim and lightweight design and can use a single battery cell as its power source.

[0174] The third aspect of this application provides a filler comprising a skeleton matrix and an adaptive material disposed on the skeleton matrix, wherein the skeleton matrix is ​​adapted to support the adaptive material, and the adaptive material is capable of expanding after absorbing electrolyte.

[0175] The filler provided in this application can be used in batteries. As an example, the filler is placed inside the battery casing to provide restraint for the battery core. In this application embodiment, the framework matrix plays a role in dispersing and supporting the adaptive material. After the adaptive material comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption, and then gradually expand and deform.

[0176] After the filler comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption. The adaptive material then expands in volume, creating a compressive restraint force on the electrode core. During normal charging and discharging, lithium insertion / extraction of charge carriers such as lithium ions causes changes in internal stress within the electrode core, resulting in cyclic expansion / contraction. At this time, the filler absorbs / releases electrolyte under the compression of the electrode core, adaptively applying a restraint force to the core. Therefore, by utilizing the elasticity and swelling properties of the adaptive material, the restraint force of the filler on the electrode core and its adaptive adjustment capability can be improved, thereby enhancing the battery's cycle performance.

[0177] In addition, a filler is placed inside the casing. In the early stage of battery cycling, the filler absorbs free electrolyte and expands to fill the gaps, thus playing a restraining role. After the electrode core has undergone multiple cycles and its volume gradually expands, the filler is squeezed and gradually releases electrolyte, replenishing the electrolyte loss during multiple cycles and improving battery performance. Therefore, it has the dual benefits of improving electrode core restraint and slow electrolyte release.

[0178] The filler provided in this application embodiment can be used in batteries. As an example, the filler is placed inside the battery casing, such as between the casing and the electrode core, or inside the electrode core, to provide direct restraint force to the battery electrode core. In this application embodiment, the skeleton matrix plays the role of supporting the adaptive material; after the adaptive material comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical actions such as diffusion, capillary action, and surface adsorption, and then gradually undergo volume expansion deformation; after being subjected to compression, it will release some electrolyte and undergo volume contraction deformation.

[0179] After the filler comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption. The adaptive material expands in volume and is confined within the space between the shell and the electrode core, or within the electrode core itself, directly exerting a compressive restraining force on the electrode core. During normal charging and discharging of the battery, lithium insertion / extraction of charge carriers such as lithium ions causes changes in the internal stress of the electrode core, resulting in cyclic expansion / contraction. At this time, the filler absorbs / releases electrolyte under the compression of the electrode core, adaptively applying a restraining force to the electrode core. The presence of the framework matrix serves two purposes: supporting the adaptive material and further ensuring the restraining force of the filler on the electrode core. Therefore, by utilizing the expansion effect of the adaptive material and the supporting effect of the framework matrix, a restraining force of the filler on the electrode core can be formed, improving the cycle performance of the battery.

[0180] In addition, a filler is placed inside the casing. In the early stage of battery cycling, the filler absorbs free electrolyte and expands to fill the gaps, thus playing a restraining role. After the electrode core has undergone multiple cycles and its volume gradually expands, the filler is squeezed and gradually releases electrolyte, replenishing the electrolyte loss during multiple cycles and improving battery performance. Therefore, it has the dual benefits of improving electrode core restraint and slow electrolyte release.

[0181] In addition, the filler provided in this application embodiment can also be applied to the electrode core expansion caused by the formation and growth of the SEI film in the electrode, physical and electrochemical expansion, gas generation expansion, etc., so as to apply an adaptive restraining force to protect the battery safety.

[0182] In some embodiments of this application, the battery satisfies at least one of the following (I) to (III):

[0183] (I) The framework matrix is ​​a porous network structure, and at least part of the adaptive material is dispersed in the porous network structure of the framework matrix;

[0184] (II) The framework matrix can expand after absorbing electrolyte;

[0185] (III) The skeleton matrix is ​​elastic.

[0186] The framework matrix has a porous network structure, which is beneficial for dispersing the adaptive material and can exhibit a certain degree of elasticity. Both the "framework matrix" and the "adaptive material" have certain expansion characteristics. The "framework matrix" has relatively high elasticity and can quickly recover its original shape after the external force is weakened or removed. The "adaptive material" has relatively strong creep. After the adaptive material comes into contact with the electrolyte, the solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption, and then gradually expand and deform.

[0187] After the filler comes into contact with the electrolyte, solvent molecules in the electrolyte enter the adaptive material through physical processes such as diffusion, capillary action, and surface adsorption. The adaptive material expands in volume, and the framework matrix adapts to the volume change of the adaptive rubber material, resulting in overall expansion of the filler. This expansion creates a compressive restraint force on the electrode core. During normal charging and discharging, lithium insertion / extraction of charge carriers such as lithium ions causes changes in the internal stress of the electrode core, leading to cyclic expansion / contraction. At this time, the filler absorbs / releases electrolyte under the compression of the electrode core, adaptively applying a restraint force to the electrode core. Therefore, by utilizing the expansion effect of the "framework matrix" and the "adaptive material," as well as the synergistic effect of the elasticity of the "framework matrix" and the swelling property of the "adaptive material," the restraint force of the filler on the electrode core and its adaptive adjustment capability can be improved, thereby improving the cycle performance of the battery.

[0188] The skeleton matrix can expand after absorbing electrolyte. On the one hand, the skeleton matrix can play a similar role to the restraining force of the electrode core as the adaptive material. On the other hand, it makes the skeleton matrix have a certain elasticity, which can adapt to the volume expansion or contraction changes of the adaptive material, and has resilience, thus improving the overall adaptive restraining force adjustment capability of the filler.

[0189] In some embodiments of this application, the framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

[0190] In this embodiment, the adaptive material has a particulate structure, which is beneficial for better dispersion in the porous network matrix. By utilizing the elastic effect of the "matrix matrix" and the "adaptive material", as well as the synergistic effect of the resilience of the "matrix matrix" and the swelling property of the "adaptive material", the binding force of the filler on the electrode core and the adaptive adjustment capability of the binding force can be improved, thereby improving the cycle performance of the battery.

[0191] In some embodiments of this application, the filler satisfies at least one of the following (i) and (ii):

[0192] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0193] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0194] In this embodiment, the material of the skeleton matrix includes, but is not limited to, at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene. These materials are porous materials that can provide a three-dimensional mesh structure. This application has good elasticity and is suitable for expansion after absorbing electrolyte. As the core volume expands / contracts, the core exerts a squeezing effect on the filler, allowing the adaptive material to adaptively absorb / release electrolyte, forming an adaptive restraining force on the core. It can also disperse more adaptive material and use its resilience to restrain the elastic rubber, thereby improving the overall adaptive restraining force of the filler on the core.

[0195] In the embodiments of this application, the adaptive material includes, but is not limited to, at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber. These materials can absorb electrolyte and adapt accordingly, have good elasticity and creep properties, and are suitable for expansion after absorbing electrolyte. As the core volume expands / contracts, the core exerts a squeezing effect on the filler, causing the adaptive material to adaptively absorb / release electrolyte and form an adaptive restraining force on the core.

[0196] In some embodiments of this application, the mass ratio of the adaptive material to the skeleton matrix is ​​6:4 to 9:1.

[0197] In this embodiment, the mass ratio of the adaptive material to the skeleton matrix meets the above requirements. On the one hand, this helps to fully utilize the creep property of the adaptive material, and on the other hand, it enables the skeleton matrix to provide a certain rigid support and resilience, thereby allowing the filler as a whole to directly form a good adaptive restraint force on the pole core.

[0198] As examples, the mass ratio of the adaptive material to the skeleton matrix is ​​6:4, 7:3, 8:2, 9:1, etc.

[0199] The fourth aspect of this application discloses a method for preparing a filler, comprising:

[0200] The filler is obtained by mixing the material of the skeleton matrix with the adaptive material, wherein the adaptive material is disposed on the skeleton matrix, the skeleton matrix is ​​adapted to support the adaptive material, and the adaptive material can expand after absorbing the electrolyte.

[0201] The filler prepared in this embodiment can utilize the expansion effect of the adaptive material and the support effect of the skeleton matrix to form a restraining force on the electrode core, thereby improving the cycle performance of the battery. It can also improve the restraining force of the filler on the electrode core and the adaptive adjustment capability of the restraining force, thus improving the cycle performance of the battery.

[0202] In some embodiments of this application, the mixing of the skeleton matrix material and the adaptive material includes: impregnating the skeleton matrix material and the dispersion of the adaptive material to obtain an impregnated part, and hot-pressing the impregnated part to obtain a filler.

[0203] The preparation method provided in this application first diffuses the adaptive material into the skeleton matrix through impregnation, and then forms the filler through hot pressing. The preparation method is simple and easy to operate.

[0204] In some embodiments of this application, the method for preparing the filler includes:

[0205] Step S100. Provide a dispersion of the adaptive material; it can be prepared by yourself or a pre-prepared dispersion can be used.

[0206] Step S200. Mix the material of the skeleton matrix with the dispersion liquid and perform impregnation treatment; the dispersion uniformity and dispersion amount of the expanding material in the skeleton matrix can be controlled by controlling factors such as the concentration of the dispersion liquid and the impregnation time.

[0207] Step S300. After impregnation, the impregnated part is obtained. The impregnated part is then subjected to hot pressing to obtain the filler. After hot pressing, a film structure without continuous pores can be obtained.

[0208] In some embodiments of this application, the preparation method satisfies at least one of the following (i) and (ii):

[0209] (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene;

[0210] (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

[0211] In the embodiments of this application, the material of the skeleton matrix includes, but is not limited to, at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene. These materials are porous materials that can provide a three-dimensional mesh structure and can expand when absorbing electrolyte and contract when releasing electrolyte, exhibiting good elasticity. Furthermore, they can disperse more elastic rubber, utilizing its resilience to constrain the elastic material and improve the overall adaptive restraint force of the filler on the electrode core.

[0212] In the embodiments of this application, the adaptive material includes, but is not limited to, at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber. These materials can absorb electrolyte and adapt accordingly. They can expand when absorbing electrolyte and contract when releasing electrolyte, and have good elasticity and creep properties. As the core volume expands / contracts, the core exerts a squeezing effect on the filler, so that the adaptive material absorbs / releases electrolyte at the same time, forming an adaptive restraint force on the core.

[0213] In some embodiments of this application, the dispersion satisfies at least one of the following:

[0214] (α) The dispersion is an emulsion;

[0215] (β) The dispersed phase of the dispersion includes an adaptive material, and the continuous phase includes at least one of water and an organic solvent;

[0216] (γ) Based on the total mass of the dispersion, the mass fraction of the dispersed phase in the dispersion is 5% to 80%.

[0217] In this embodiment, the mass fraction of the dispersion meets the above conditions, which helps to maintain a certain fluidity of the dispersion and promotes the diffusion of the adaptive material into the skeleton matrix along with the dispersion. This allows the skeleton matrix to effectively load the required amount of adaptive material, fully utilize the resilience and creep of the filler, and when applied to a battery, can fully utilize the adaptive restraint force of the filler on the electrode core, thereby improving battery performance.

[0218] As an example, the mass fraction of the dispersion is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc. The mass fraction of the dispersion can be determined by measuring the mass of the dispersion before and after drying.

[0219] In this embodiment, the adaptive material is the aforementioned adaptive rubber, and the dispersion is in emulsion form. The adaptive rubber emulsion is a colloidal dispersion system, where the dispersed phase is adaptive rubber particles, and the continuous phase is water or other solvents. The adaptive rubber emulsion can be prepared by methods such as emulsion polymerization or solution polymerization, wherein the rubber particles are generated through a polymerization reaction.

[0220] In some embodiments of this application, the step of hot-pressing the impregnated part, i.e. the material of the impregnated skeleton substrate, satisfies at least one of the following (a) and (b);

[0221] (a) The hot pressing temperature is 40℃~130℃;

[0222] (B) The hot pressing pressure is 0.5MPa to 50MPa.

[0223] Hot-pressing temperature and hot-pressing pressure are two commonly used parameters in material processing, referring to the temperature and pressure applied during the hot-pressing process, respectively. Hot-pressing temperature refers to the temperature caused by the heat applied during hot-pressing. This temperature is usually higher than the material's room temperature to facilitate plastic deformation and bonding. The hot-pressing temperature needs to be determined based on the material's properties and specific processing requirements, and is typically below the material's melting point. Hot-pressing pressure refers to the pressure applied during the hot-pressing process. This pressure is usually applied by a press or other mechanical equipment, and its function is to cause the powder or preform to undergo plastic deformation at high temperatures, thereby forming a dense material. The selection of the hot-pressing pressure also needs to be determined based on the material's properties and specific processing requirements.

[0224] The testing methods for hot pressing temperature and pressure can be refined according to specific application scenarios and equipment, but generally include the following steps: 1. Equipment selection: Select a suitable press or other hot pressing equipment to ensure that the equipment can accurately control temperature and pressure. 2. Sample preparation: Prepare samples according to test requirements, such as powders, preforms, etc. 3. Parameter setting: Set the hot pressing temperature and pressure according to the material properties and processing requirements. 4. Hot pressing process: Place the sample in the equipment and perform hot pressing according to the set parameters. During this process, it is necessary to closely monitor the temperature and pressure to ensure that they remain stable at the set values. 5. Data recording: Record the temperature and pressure changes throughout the entire hot pressing process.

[0225] For example, the hot pressing temperatures are 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, etc.

[0226] For example, the hot pressing pressures are 0.5MPa, 1MPa, 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, 45MPa, 50MPa, etc.

[0227] The values ​​of hot pressing temperature and hot pressing pressure used in the preparation method can be determined based on the material of the skeleton matrix and the temperature and pressure resistance properties of the adaptive material.

[0228] It should be noted that the features and advantages described above for the battery in the first aspect of this application also apply to the filler prepared in the fourth aspect of this application, and will not be repeated here.

[0229] The following will explain the solution of this application with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0230] I. Battery Preparation

[0231] Example 1

[0232] 1. Preparation of positive electrode sheet

[0233] The positive electrode active material LiFePO4, conductive agent carbon black, and binder PVDF are thoroughly mixed at a mass ratio of 95:2.5:2.5. The solvent NMP is added, and the mixture is stirred under vacuum until the slurry is uniformly mixed to obtain the positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the current collector aluminum foil. After the electrode is dried, it is rolled and die-cut to obtain the positive electrode sheet.

[0234] 2. Preparation of negative electrode sheet

[0235] The negative electrode active material graphite, conductive agent carbon black, binder SBR, and thickener CMC are mixed in a mass ratio of 93:1:4:2. Deionized water is added as a solvent, and the mixture is stirred in a vacuum mixer until the slurry is homogeneous to obtain the negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the current collector copper foil. After the electrode is dried, it is rolled and die-cut to obtain the negative electrode sheet.

[0236] 3. Preparation of electrolyte

[0237] In an argon-filled glove box, ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain a mixed solvent. Lithium hexafluorophosphate (LiPF6), vinylene carbonate (VC), methylene disulfonate (MMDS), and 2,6-di-tert-butyl-4-methylphenol (BHT) were then added to the mixed solvent to obtain the electrolyte. Based on the total mass of the electrolyte, the mass percentages of lithium hexafluorophosphate were 12%, vinylene carbonate 5%, methylene disulfonate 1%, and 2,6-di-tert-butyl-4-methylphenol 0.5%.

[0238] 4. Preparation of the separating membrane

[0239] The diaphragm is a PE-coated ceramic diaphragm with a thickness of 12μm.

[0240] 5. Preparation of the shell

[0241] The filler composition, calculated by mass percentage, is: styrene-butadiene rubber, 60%; polypropylene diaphragm, 40%.

[0242] The manufacturing process for forming the filler on the inner surface of the shell is as follows:

[0243] ①Immerse the polypropylene backbone matrix in a 40% (w / w) styrene-butadiene rubber latex for 1 minute. The solvent of the styrene-butadiene rubber latex is water.

[0244] ②After impregnation, the polypropylene skeleton matrix with styrene-butadiene rubber is removed, and the filler is obtained after hot pressing at 5MPa and 80℃ for 5s;

[0245] ③ The filler is cut to the same size as the outer surface of the large surface of the pole core. The outer surface area of ​​the large surface of the pole core is 18*32mm and the thickness is 1% of the total thickness of the shell. It is then hot-pressed onto the inner surface of the shell (aluminum-plastic film with an inner thickness of 5mm) to obtain the improved aluminum-plastic film.

[0246] 6. Preparation of lithium-ion batteries

[0247] The negative electrode, separator, positive electrode, and separator are stacked in sequence, and the above sequence is repeated to fix them with high-temperature resistant tape. Then, the positive and negative electrode tabs are welded, and the cells are encapsulated with an improved aluminum-plastic film to obtain the battery cell. After vacuum drying the battery cell at 80°C for 72 hours, the corresponding electrolyte is injected and it is encapsulated. Then, through steps such as standing, pressurized formation, aging, venting, and capacity testing, a square lithium-ion battery is obtained.

[0248] Example 2-Example 23

[0249] The specific parameter differences between Examples 2-23 and Example 1 are shown in Tables 1-1 and 1-2.

[0250] Comparative Example 1

[0251] This embodiment uses the method of Embodiment 1, the difference being that the shell is made of aluminum-plastic film and no filler is added.

[0252] Comparative Example 2

[0253] This embodiment uses the method of Embodiment 1, the difference being that the preparation of the shell is different. Specifically:

[0254] The raw material composition of the filler, calculated by mass percentage, is 100% polypropylene membrane.

[0255] The manufacturing process for forming the filler on the inner surface of the shell is as follows:

[0256] The polypropylene diaphragm is cut to the same size as the outer surface of the electrode core. The outer surface area of ​​the electrode core is 18*32mm, and the thickness is 1% of the total thickness of the shell. It is then hot-pressed onto the inner surface of the shell (aluminum-plastic film with an inner thickness of 5mm) to obtain the improved aluminum-plastic film.

[0257] Comparative Example 3

[0258] This embodiment uses the method of Embodiment 1, the difference being that the preparation of the shell is different. Specifically:

[0259] The raw material composition of the filler, calculated by mass percentage, is 100% styrene-butadiene rubber.

[0260] The manufacturing process for forming the filler on the inner surface of the shell is as follows:

[0261] Styrene-butadiene rubber is cut to the same size as the outer surface of the electrode core. The outer surface area of ​​the electrode core is 18*32mm, and the thickness is 1% of the total thickness of the shell. It is then hot-pressed onto the inner surface of the shell (aluminum-plastic film with an inner thickness of 5mm) to obtain the improved aluminum-plastic film.

[0262] For the parameters of Examples 1-23 and Comparative Examples 1-3, please refer to Tables 1-1 and 1-2.

[0263] Thickness before expansion indicates the percentage of the filler relative to the total thickness within the shell before expansion; therefore, the unit is %.

[0264] Thickness after expansion represents the percentage of the filler relative to the total thickness within the shell after expansion; therefore, the unit is %.

[0265] The area of ​​the filler is a percentage of the orthographic projection area of ​​the filler along the thickness direction relative to the outer surface area of ​​any large facet of the pole core; therefore, the unit is %.

[0266] II. Performance Testing

[0267] 1. Testing Method

[0268] (1) Cyclic performance

[0269] The experimental samples were subjected to cyclic testing using a blue electric current testing system. The specific cyclic testing steps are as follows:

[0270] The battery was charged at 2.2C constant current and constant voltage to 4.18V, then stopped at 1.8C; charged at 1.8C constant current and constant voltage to 4.23V, then stopped at 1.65C; charged at 1.65C constant current and constant voltage to 4.28V, then stopped at 1.5C; charged at 1.5C constant current and constant voltage to 4.33V, then stopped at 0.8C; charged at 0.8C constant current and constant voltage to 4.45V, then stopped at 0.025C, and then left to rest for 10 minutes. It was then discharged at 1.0C to 3.0V, and left to rest for 10 minutes. The test temperature was 25℃. The capacity decay curve was obtained by comparing the capacity at each step with the initial capacity. The ratio of the capacity at 1000 cycles to the capacity at the first cycle was recorded as the battery's cycle capacity retention rate.

[0271] (2) Electron microscopy scanning: A Hitachi SU8010 electron microscope was used with an energy consumption of 1 kV.

[0272] 2. Test Results

[0273] (1) The performance of the lithium-ion batteries prepared in Examples 1-23 and Comparative Examples 1-3 was tested, as shown in Table 2.

[0274] As shown in Table 2, the embodiments of this application improve the cycle capacity retention rate of the battery by providing a filler between the shell and the electrode core. As shown in Examples 1-4, with the increase of the amount of styrene-butadiene rubber filling the skeleton matrix, the restraining force on the electrode core is better, and the cycle capacity retention rate of the battery shows a gradual increasing trend, eventually stabilizing. As shown in Examples 5-9, with the increase of the filler thickness and filling area, the cycle capacity retention rate of the battery shows an increasing trend. Various preparation parameters, such as hot-pressing temperature and hot-pressing pressure, have relatively little impact on the performance of the filler, and the cycle capacity retention rate of the battery shows a relatively stable trend. In contrast, the batteries provided in Comparative Examples 1-3 have a lower cycle capacity retention rate than those in the embodiments of this application.

[0275] Table 2

[0276] (2) As shown in Figure 5, it is a cross-sectional electron microscope image of the polypropylene membrane (PE) used in Example 1. In the figure, "PE" refers to the polypropylene membrane. It can be seen from the figure that the polypropylene membrane has a porous mesh structure. As shown in Figure 6, it is a cross-sectional electron microscope image of the filler prepared in Example 1. In the figure, styrene-butadiene rubber is filled in the mesh structure to form a structure similar to a solid.

[0277] Figure 7 shows a comparison of the cycle performance test results of the batteries obtained in Examples 1, 2, and Comparative Example 1 of this application. In the figure, "Spec" refers to the target curve; "Experiment 1" refers to the battery prepared in Example 1; "Experiment 2" refers to the battery prepared in Example 2; and "Control Group" refers to the battery prepared in Comparative Example 1. It can be seen from the figure that the cycle performance of the battery prepared in the examples of this application is superior to that of the battery obtained in Comparative Example 1.

[0278] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A battery, wherein, The device includes a housing, which houses the electrode core, and a filler. The filler is disposed at least at one of the two locations: between the housing and the pole core, and inside the pole core; The filler includes a skeleton matrix and an adaptive material disposed on the skeleton matrix. The skeleton matrix supports the adaptive material, which can expand after absorbing electrolyte to generate a restraining force on the electrode core.

2. The battery according to claim 1, wherein, Satisfy at least one of the following (I) to (III): (I) The framework matrix is ​​a porous network structure, and at least a portion of the adaptive material is dispersed in the porous network structure of the framework matrix; (II) The skeleton matrix is ​​able to expand after absorbing the electrolyte; (III) The skeleton matrix has resilience.

3. The battery according to claim 1, wherein, The framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

4. The battery according to any one of claims 1-3, wherein, Satisfy at least one of the following (i) and (ii): (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene; (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

5. The battery according to any one of claims 1-4, wherein, In the filler, the mass ratio of the adaptive material to the skeleton matrix is ​​6:4 to 9:

1.

6. The battery according to any one of claims 1-5, wherein, The thickness of the filler after absorbing the electrolyte is 0.1% to 30% of the total thickness of the shell.

7. The battery according to any one of claims 1-6, wherein, The filler is arranged corresponding to the large surface area of ​​the pole core, and satisfies at least one of the following (A) and (B): (A) The filler is disposed between the large surface of the pole core and the shell; (B) The filler is disposed inside the pole core at a position corresponding to the large surface of the pole core.

8. The battery according to any one of claims 1-6, wherein, The filler is arranged corresponding to the large surface area of ​​the pole core, and satisfies at least one of the following (a) and (b): (a) The filler is disposed on the inner wall of the housing facing the large surface of the pole core; (b) The filler is disposed on the outer surface of the large surface of the pole core.

9. The battery according to claim 8, wherein, The filler is located in the empty foil area on the outer surface of the large surface of the pole core.

10. The battery according to any one of claims 7-9, wherein, The filler has a layered structure, and the orthographic projection area of ​​the filler in the thickness direction is 20% to 130% of the outer surface area of ​​the large surface of the pole core.

11. The battery according to any one of claims 1-10, wherein, The electrode core includes multiple cores, and the filler is provided between two adjacent electrode cores.

12. The battery according to any one of claims 1-11, wherein, The shape of the filler when projected orthogonally in the thickness direction includes at least one of the following: rectangle, triangle, square, and irregular shape.

13. The battery according to any one of claims 1-12, wherein, The structure of the pole core satisfies at least one of the following (a) and (b): (a) The pole core includes one or a combination of two of the following: a wound pole core and a stacked pole core; (b) The electrode core includes a positive electrode plate, a negative electrode plate, and an isolation structure, the isolation structure being adapted to insulate the positive electrode plate and the negative electrode plate from each other.

14. The battery according to any one of claims 1-13, wherein, It also includes an electrolyte that satisfies at least one of the following conditions (①) and (②): (①) The electrolyte is filled between the electrode core and the shell; (②) The electrolyte is filled inside the electrode core.

15. An electrical appliance, wherein, Includes the battery as described in any one of claims 1-14.

16. A filler, wherein, It includes a framework matrix and an adaptive material disposed on the framework matrix, the framework matrix being adapted to support the adaptive material, the adaptive material being capable of expanding after absorbing electrolyte.

17. The filler according to claim 16, wherein, Satisfy at least one of the following (I) to (III): (I) The framework matrix is ​​a porous network structure, and at least a portion of the adaptive material is dispersed in the porous network structure of the framework matrix; (II) The skeleton matrix is ​​able to expand after absorbing the electrolyte; (III) The skeleton matrix has resilience.

18. The filler according to claim 16, wherein, The framework matrix is ​​a layered structure with a porous network structure, and the adaptive material is a particulate structure, with at least a portion of the adaptive material dispersed in the porous network structure of the framework matrix.

19. The filler according to any one of claims 16-18, wherein, Satisfy at least one of the following (i) and (ii): (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene; (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

20. The filler according to any one of claims 16-19, wherein, The mass ratio of the adaptive material to the skeleton matrix is ​​6:4 to 9:

1.

21. A method for preparing a filler, wherein, include: A filler is obtained by mixing the material of the skeleton matrix with an adaptive material, wherein the adaptive material is disposed on the skeleton matrix, the skeleton matrix is ​​adapted to support the adaptive material, and the adaptive material is capable of expanding after absorbing electrolyte.

22. The preparation method according to claim 21, wherein, The mixing of the skeleton matrix material with the adaptive material includes: impregnating the skeleton matrix in a dispersion of the adaptive material to obtain an impregnated part, and hot-pressing the impregnated part to obtain the filler.

23. The preparation method according to claim 22, wherein, Satisfy at least one of the following (i) and (ii): (i) The material of the skeleton matrix includes at least one of polyethylene, polypropylene, and a composite material of polyethylene and polypropylene; (ii) The adaptive material includes at least one of nitrile rubber, styrene-butadiene rubber, and ethylene propylene diene monomer (EPDM) rubber.

24. The preparation method according to claim 22 or 23, wherein, The dispersion meets at least one of the following conditions: (α) The dispersion is an emulsion; (β) The dispersed phase of the dispersion includes an adaptive material, and the continuous phase includes at least one of water and an organic solvent; (γ) Based on the total mass of the dispersion, the mass fraction of the dispersed phase in the dispersion is 5% to 80%.

25. The preparation method according to any one of claims 22-24, wherein, In the hot pressing step, at least one of the following (a) and (b) is satisfied; (a) The hot pressing temperature is 40℃~130℃; (B) The hot pressing pressure is 0.5MPa to 50MPa.

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