Gel polymer electrolytes, batteries, and electrical devices

Abstract

This application discloses a gel polymer electrolyte, a battery, and an electrical device. The gel polymer electrolyte comprises an electrolyte in which thermally conductive particles are dispersed, the thermal conductivity coefficient of the thermally conductive particles at 25°C being 400 W / mK or higher.

Description

Technical Field

[0001] This application belongs to the field of batteries, and specifically relates to gel polymer electrolytes, batteries, and electrical devices.

Background Art

[0002] Lithium-ion batteries have characteristics such as being green, environmentally friendly, high-energy, and low-carbon. They are not only used in energy storage systems such as hydroelectric, thermal, wind, and solar power plants, but also widely used in many fields such as electric vehicles, electric motorcycles, electric bicycles, and electric transportation means, as well as military equipment and aerospace. With the development of modern society, people's requirements for lithium-ion batteries are becoming increasingly high, and the research on semi-solid batteries is also becoming increasingly active.

Summary of the Invention

[0003] In view of the technical problems existing in the background art, this application provides a gel polymer electrolyte for improving the curing uniformity of a gel polymer matrix.

[0004] <0000ID=24]]

[0005] The gel polymer electrolyte of this application has at least the following beneficial effects. By introducing thermally conductive particles into the electrolyte solution, the temperature uniformity of the electrolyte solution is improved, thereby improving the curing uniformity of the polymer matrix in the in-situ polymerization reaction process, and improving the impedance and elastic modulus of the gel polymer electrolyte matrix, as well as the kinetic performance of the battery.

[0006] In some embodiments of this application, the electrical conductivity of the thermally conductive particles at 25 °C is 10 -7 S / cm or less, and optionally, 10 -16 S / cm to 10 -7 ​The conductivity is S / cm. By controlling the electrical conductivity of the thermally conductive particles within a predetermined range, it is difficult to increase the electronic conductivity of the electrolyte, and the ionic conductivity of the electrolyte does not change significantly.

[0007] In some embodiments of this application, the thermal conductivity coefficient is 400 W / mK to 2000 W / mK.

[0008] In some embodiments of this application, the thermally conductive particles include diamond-like carbon. Satisfying this condition allows the thermally conductive particles to have a high thermal conductivity and low electrical conductivity, is advantageous in improving the uniformity of curing during the in-situ polymerization reaction of the polymer matrix, and is advantageous in improving the kinetic performance of the battery by reducing the probability of self-discharge problems occurring.

[0009] In some embodiments of this application, the atomic percentage of hydrogen in the diamond-like carbon is 50 at% or less, selectively 20 at% or less, and more selectively 10 at% or less, relative to the total number of atoms in the diamond-like carbon. Controlling the hydrogen content in the diamond-like carbon within a predetermined range is advantageous for improving the curing uniformity of the polymer matrix during the in-situ polymerization reaction process, and is also advantageous for improving the kinetic performance of the battery by reducing the probability of self-discharge problems occurring.

[0010] In some embodiments of this application, the number of sp atoms in the diamond-like carbon is determined based on the total number of carbon atoms in the diamond-like carbon. 3 The atomic percentage of bonded carbon is 20 at% to 85 at%, and selectively 70 at% to 85 at%. sp in diamond-like carbon. 3 Controlling the content of bound carbon within a predetermined range is advantageous for improving the uniformity of curing of the polymer matrix during the in-situ polymerization reaction process, and also for reducing the probability of battery self-discharge problems, thereby improving the kinetic performance of the battery and balancing the difficulty and cost of manufacturing diamond-like carbon.

[0011] In some embodiments of this application, the particle size of the thermally conductive particles is 10 μm or less. Controlling the particle size of the thermally conductive particles within a predetermined range is advantageous in improving the temperature uniformity of the electrolyte and the curing uniformity of the gel polymer matrix, as well as in providing the battery with good electrochemical performance.

[0012] In some embodiments of this application, the concentration of the thermally conductive particles is 0.1 wt% to 5 wt%, and selectively 0.5 wt% to 2 wt%, relative to the total mass of the gel polymer electrolyte. Controlling the concentration of thermally conductive particles in the electrolyte within a predetermined range is advantageous for improving the effect of the thermally conductive particles on the curing uniformity of the gel polymer matrix, and is also advantageous for obtaining a better active ion transport effect.

[0013] In some embodiments of this application, the gel polymer electrolyte further comprises a gel polymer matrix in which the thermally conductive particles are dispersed.

[0014] A second aspect of this application provides a battery comprising a gel polymer electrolyte according to the first aspect of this application. The battery of this application has the features and effects described for the gel polymer electrolyte of the first aspect of this application. In short, the battery has excellent kinetic performance.

[0015] In some embodiments of this application, the battery further comprises a positive electrode sheet, a negative electrode sheet, and a separator, wherein at least one of the positive electrode sheet, the negative electrode sheet, and the separator contains the thermally conductive particles. Satisfying this condition is advantageous for further improving the temperature uniformity of the electrolyte and improving the curing uniformity of the polymer matrix in the in-situ polymerization reaction process.

[0016] In some embodiments of this application, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on the positive electrode current collector, wherein the positive electrode active material layer includes the thermally conductive particles. The inclusion of thermally conductive particles in the positive electrode active material layer is advantageous not only for further improving the curing uniformity of the polymer matrix during the in-situ polymerization reaction process, but also for improving the heat dissipation effect and temperature uniformity of the battery during use.

[0017] In some embodiments of this application, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector, wherein the negative electrode active material layer contains the thermally conductive particles, or the negative electrode sheet comprises a negative electrode current collector and a thermal conductive layer provided on the negative electrode current collector, wherein the thermal conductive layer contains the thermally conductive particles. Including thermally conductive particles in the negative electrode sheet is advantageous not only for further improving the curing uniformity of the polymer matrix in the in-situ polymerization reaction process, but also for improving the heat dissipation effect and temperature uniformity of the battery during use.

[0018] In some embodiments of this application, the mass ratio of the thermally conductive particles in the positive electrode active material layer is 0.1 wt% to 2 wt%. Controlling the mass ratio of the thermally conductive particles in the positive electrode active material layer within a predetermined range is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and is also advantageous for achieving both the conductivity of the positive electrode sheet and the energy density of the battery.

[0019] In some embodiments of this application, the mass ratio of the thermally conductive particles in the negative electrode active material layer is 0.1 wt% to 4 wt%. Controlling the mass ratio of the thermally conductive particles in the negative electrode active material layer within a predetermined range is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and is also advantageous for achieving both the conductivity of the negative electrode sheet and the energy density of the battery.

[0020] In some embodiments of this application, the negative electrode active material layer comprises a silicon material, and the mass ratio of silicon elements in the negative electrode active material layer is 10 wt% or more. Controlling the mass ratio of silicon elements in the negative electrode active material layer within a predetermined range is advantageous for improving the energy density of the negative electrode sheet and the battery.

[0021] In some embodiments of this application, the thickness of the thermal conductive layer is 50 nm to 5 μm, and / or the mass ratio of the thermal conductive particles in the thermal conductive layer is 50 wt% or more. Satisfying these predetermined conditions is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and is also advantageous for achieving both the conductivity of the negative electrode sheet and the energy density of the battery.

[0022] In some embodiments of this application, the thermal conductive layer further comprises a conductive agent and / or an adhesive, wherein the mass ratio of the conductive agent in the thermal conductive layer is 0.1 wt% to 40 wt%, selectively 5 wt% to 15 wt%, and the mass ratio of the adhesive in the thermal conductive layer is 0.01 wt% to 5 wt%. Controlling the content of the conductive agent and / or adhesive in the thermal conductive layer within a predetermined range is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and is also advantageous for achieving both the conductivity of the negative electrode sheet and the adhesion strength of the conductive layer.

[0023] In some embodiments of this application, the mass ratio of the thermally conductive particles in the electrolyte is equal to or greater than the mass ratio of the thermally conductive particles in the negative electrode active material layer. Satisfying the predetermined conditions is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and at the same time, it is also advantageous for considering the energy density of the battery.

[0024] In some embodiments of this application, the mass ratio of the thermally conductive particles in the negative electrode active material layer is equal to or greater than the mass ratio of the thermally conductive particles in the positive electrode active material layer. Satisfying the predetermined conditions is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery.

[0025] A third aspect of this application provides an electrical device, the electrical device including a battery according to a second aspect of this application.

[0026] Additional aspects and advantages of this application are, in part, described below, some of which become apparent from this description, or can be understood through the practice of this application. [Brief explanation of the drawing]

[0027] The above and / or additional aspects and advantages of this application will become apparent and readily apparent from the description of embodiments based on the following drawings, hereby

[0028] [Figure 1] This is a schematic diagram of the structure of a battery according to one embodiment of this application. [Figure 2] This is a schematic diagram of the structure of a battery module according to one embodiment of this application. [Figure 3] This is a schematic diagram of the structure of a battery pack according to one embodiment of this application. [Figure 4] This is an exploded view of a battery pack according to one embodiment of the present application. [Figure 5] This is a schematic diagram of one embodiment of an electrical device using a battery as a power source, according to one embodiment of the present application. [Explanation of Symbols]

[0029] 1: Rechargeable battery, 2: Battery module, 3: Battery pack, 4: Upper casing, 5: Lower casing. [Modes for carrying out the invention]

[0030] The present application will be further described below in conjunction with specific embodiments. Please understand that these specific embodiments are used solely for the purpose of illustrating the present application and are not intended to limit the scope of the application.

[0031] The “Examples” as used in this application mean that certain features, structures, or properties described in conjunction with the Examples may be included in at least one Example of this application. The appearance of the phrase in various parts of the specification does not necessarily all refer to the same Example, nor do they represent mutually exclusive or alternative Examples. Those skilled in the art will understand, both explicitly and implicitly, that the Examples described in this application may be combined with other Examples.

[0032] The “range” disclosed in this application is limited in the form of a lower limit and / or upper limit, and a given range is limited by selecting one lower limit and / or one upper limit that define the boundary of a particular range. The range thus limited may include or exclude endpoints and may be in any combination; that is, any lower limit may be combined with any upper limit to form an unspecified range, and any lower limit may be combined with other lower limits to form an unspecified range, and similarly, any upper limit may be combined with other arbitrary upper limits to form an unspecified range. Each independently disclosed point or individual numerical value itself may, as a lower limit or upper limit, be combined with any other point or individual numerical value, or with other lower limits or upper limits, to form an unspecified range.

[0033] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form novel technical solutions, and such solutions should be deemed to be included in the disclosure of this application.

[0034] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form novel technical concepts, and such technical concepts should be deemed to be included in the disclosure of this application.

[0035] Unless otherwise specified, the terms "include" and "inclusive" as used in this application refer to an open or closed type. For example, "include" and "inclusive" may include or include other components not listed, or they may include or include only the listed components. In this application, the terms "multiple" and "multiple types" refer to two or more.

[0036] Unless otherwise specified, the term "and / or" in this application simply describes the relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent three cases: A alone, A and B as a combination, or B alone. Furthermore, the letter " / " in this specification generally indicates that the preceding and succeeding related objects are in an "or" relationship.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally understood by those skilled in the art to which this application pertains. The terms used in this application are intended solely to describe specific embodiments and are not intended to limit this application. The terms “including” and “having” and any synonyms thereof in the description and claims of this application, as well as in the description of the drawings above, are intended to cover non-exclusive inclusion. Unless otherwise stated, the terms used in this application have the meanings generally understood by those skilled in the art. Unless otherwise stated, the numerical values ​​of each parameter mentioned in this application can be measured by various measurement methods commonly used in the art (for example, they can be tested according to the methods described in the embodiments of this application).

[0038] With the promotion of green environmental protection themes, lithium-ion batteries have already become deeply integrated into every aspect of life, including vehicles, electronic devices, and energy storage devices. However, as their applications deepen, some of their potential problems are also attracting increasing attention. Conventional liquid electrolytes have low boiling points, are prone to leakage, and are susceptible to problems such as lithium dendrite growth and leakage. Gel polymer electrolytes are intermediate between liquid and solid electrolytes and are advantageous in improving problems such as electrolyte leakage and lithium dendrite growth.

[0039] Currently, when gel polymer electrolytes are used in batteries, it is common practice to mix the polymerizable monomers and / or prepolymers of the gel polymer matrix with a solvent, lithium salt, initiator, etc., to form a liquid solution. Then, the liquid solution is injected into a battery case equipped with an electrode assembly and sealed. The polymerizable monomers and / or prepolymers are then polymerized in situ at high temperatures and cured to form a gel-like three-dimensional network structure. However, in the in-situ curing process of gel polymers, thermal conduction tends to be uneven. This uneven thermal conduction easily leads to unevenness in the in-situ polymerization reaction, resulting in a very high degree of polymerization in some areas while the degree of polymerization is low or almost absent in others. This can easily lead to problems such as increased internal resistance, increased polarization, and a decrease in cycle capacity retention and cycle life, affecting the dynamic performance of the battery.

[0040] In this application, by introducing thermally conductive particles into the electrolyte, the uniformity of the gel polymer matrix in the in-situ curing process can be improved, and by controlling the thermal conductivity coefficient of the thermally conductive particles at 25°C to 400 W / mK or higher, it is advantageous to obtain an even better improvement effect.

[0041] The gel polymer electrolyte disclosed in the embodiments of this application is suitable for gel batteries, i.e., semi-solid batteries, and the batteries disclosed in the embodiments of this application can be used in electrical devices that use the battery as a power source or in various energy storage systems that use the battery as an energy storage element. Examples of electrical devices include, but are not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, electric bicycles, electric automobiles, ships, and spacecraft. Examples of electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric steamship toys, and electric airplane toys, and examples of spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0042] A first aspect of this application provides a gel polymer electrolyte comprising an electrolyte in which thermally conductive particles are dispersed, wherein the thermal conductivity coefficient of the thermally conductive particles at 25°C is 400 W / mK or higher.

[0043] Here, the thermal conductivity coefficient of the thermally conductive particles can be measured by the hot disk method, which can be carried out by referring to GB / T 32064-2015. Specifically, the test can be carried out at 25°C in an atmospheric pressure environment. Some specific examples include the thermal conductivity coefficient of the thermally conductive particles at 25°C being 400 W / mK or higher, 700 W / mK or higher, 1000 W / mK or higher, 1300 W / mK or higher, 1600 W / mK or higher, 2000 W / mK or higher, 2500 W / mK or higher, or within a range of any of the above values. In actual operation, when testing the thermal conductivity coefficient of thermally conductive particles in the electrolyte of a battery, the thermally conductive particles can be obtained by disassembling the battery to obtain the gel polymer electrolyte, separating the electrolyte from the gel polymer matrix (for example, by centrifugal separation), filtering, drying, and separating the solid particles therein.

[0044] Introducing thermally conductive particles into the electrolyte improves the temperature uniformity of the electrolyte in different regions within the battery case, thereby improving the uniformity of the in-situ polymerization reaction of polymerizable monomers and / or prepolymers for forming the gel polymer matrix at different locations, improving the uniformity of the thickness and structural consistency of the gel polymer matrix located between the positive and negative electrodes, reducing the impedance of the gel polymer matrix, and improving the dynamic performance of the battery. Furthermore, increasing the thermal conductivity coefficient of the thermally conductive particles is also advantageous in improving the curing uniformity of the gel polymer matrix.

[0045] As a specific example, the curing uniformity of a gel polymer matrix can be measured using the mechanical and electrochemical modes of an atomic force microscope. For example, this may involve disassembling a battery containing a gel polymer electrolyte, removing the separator containing the cured gel polymer electrolyte, placing the separator on a stainless steel plate, and connecting the stainless steel to the counter electrode of the electrochemical mode of the atomic force microscope to form a test path. Using the atomic force microscope, a 10x10 dot matrix can be taken on a 5cmx5cm separator area to set up test points. The elastic modulus E of each test point can be obtained by atomic force microscopy testing in mechanical mode, and the local AC impedance Z can be measured by impedance testing in electrochemical mode. The uniformity of the distribution of elastic modulus and electrochemical impedance can reflect the curing uniformity of the gel polymer electrolyte. Here, the uniformity of the distribution of elastic modulus A E and the uniformity of the distribution of electrochemical impedance A Z Each of these can be evaluated using the following formulas.

number

number

[0046]

number

[0047] The gel polymer electrolyte of this application has at least the following advantageous effects: by introducing thermally conductive particles into the electrolyte, the temperature uniformity of the electrolyte is improved, thereby improving the curing uniformity of the polymer matrix during the in-situ polymerization reaction process, improving the impedance and elastic modulus of the gel polymer electrolyte matrix, and the dynamic performance of the battery. Furthermore, after improving the temperature uniformity of the electrolyte, it is also advantageous in improving the heat dissipation uniformity during battery use.

[0048] Furthermore, the gel polymer electrolyte of the first aspect of this application, in addition to satisfying the above conditions, can also be further optimized in terms of the performance of the gel polymer electrolyte by controlling the electrical conductivity range, thermal conductivity coefficient range, and the type, composition, particle size, and dispersion concentration of the thermal conductive particles in the gel polymer electrolyte. That is, in addition to satisfying the above conditions, one or more of the following conditions can be selectively satisfied.

[0049] In some embodiments of this application, the thermal conductivity coefficient of the thermally conductive particles may be 400 W / mK to 2000 W / mK.

[0050] For example, the thermal conductivity of thermally conductive particles may be 400 W / mK, 500 W / mK, 700 W / mK, 900 W / mK, 1100 W / mK, 1300 W / mK, 1500 W / mK, 1700 W / mK, 1900 W / mK, or 2000 W / mK, or within a range of any of the above values. Improving the thermal conductivity of thermally conductive particles is advantageous for improving the curing uniformity of the gel polymer matrix. The thermal conductivity of thermally conductive particles mainly depends on their material and structure, and as the thermal conductivity increases, the cost and / or the difficulty of material selection also increases accordingly.

[0051] By controlling the thermal conductivity of the thermally conductive particles within a predetermined range, it is advantageous for improving the improvement effect on the curing uniformity of the gel polymer matrix, and it is also advantageous for reducing the cost of the thermally conductive particles and / or the difficulty of material selection.

[0052] In some embodiments of the present application, the electrical conductivity of the thermally conductive particles at 25 °C is 10 -7 S / cm or less, and optionally, 10 -16 S / cm to 10 -7 S / cm.

[0053] For example, the electrical conductivity of the thermally conductive particles at 25 °C is 10 -7 S / cm or less, 10 -8 S / cm or less, 10 -9 S / cm or less, 10 -10 S / cm or less, 10 -11 S / cm or less, 10 -12 S / cm or less, 10 -16The value may be less than or equal to S / cm, or it may be within a range of any of the above values. The electrical conductivity of the thermally conductive particles can be tested by referring to the test method for volume electrical conductivity in GB / T 1410-2006. Specifically, the test can be conducted at 25°C and the test environment can be at normal pressure. In actual operation, when testing the thermal conductivity coefficient of thermally conductive particles in the electrolyte of a battery, the battery can be disassembled to obtain the gel polymer electrolyte and separate the thermally conductive particles. The specific separation method has been explained in the previous section and will not be explained further here. In a battery system, it is desirable for the electrolyte to have high ionic conductivity and as low as possible electronic conductivity, and in order to reduce the probability of self-discharge problems in the battery, it is desirable that the additives in the electrolyte system do not conduct electricity and do not increase the electronic conductivity of the electrolyte. For the thermally conductive particles, the lower their electrical conductivity, the worse their conductivity, and after adding the thermally conductive particles to the electrolyte, the probability of short-circuiting the circuit in the battery and self-discharge problems decreases. On the other hand, by controlling the electrical conductivity of the thermally conductive particles to satisfy a predetermined range, it becomes more difficult to increase the electronic conductivity of the electrolyte, thus reducing the probability of battery self-discharge problems. Furthermore, thermally conductive particles that satisfy this condition are less likely to be lithium-ified during charging and discharging, and their ionic conductivity does not change significantly after being added to the electrolyte.

[0054] Optionally, the electrical conductivity of thermally conductive particles at 25°C is 10 -16 S / cm~10 -7 S / cm, for example 10 -7 S / cm, 5×10 -8 S / cm, 5×10 -9 S / cm, 5×10 -10 S / cm, 5×10 -11 S / cm, 5×10 -12 S / cm, 5×10 -13 S / cm, 5×10 -14 S / cm, 5×10 -15 S / cm, 5×10 -16The values ​​may be S / cm, or within a range of any of the above values. The lower the electrical conductivity of the thermally conductive particles, the better their insulating properties become. When these particles are introduced into the electrolyte, it becomes more difficult to increase the electron conductivity of the electrolyte, and the probability of battery self-discharge problems occurring becomes relatively lower. On the other hand, as the electrical conductivity of the thermally conductive particles increases, the cost of the thermally conductive particles and / or the difficulty of material selection also increases accordingly.

[0055] By controlling the electrical conductivity of thermally conductive particles within a predetermined range, it is advantageous to reduce the probability of self-discharge occurring in the battery due to the introduction of thermally conductive particles, and also to reduce the cost of thermally conductive particles and / or the difficulty of material selection.

[0056] In some embodiments of this application, the thermally conductive particles include diamond-like carbon.

[0057] In diamond, carbon-carbon is sp 3 They are bonded in the form of a bond, and in graphite, carbon-carbon bonds are sp. 2 Bonded in a bonded manner, diamond-like carbon is amorphous carbon, and its main component is carbon, sp 3 and sp 2It contains two types of heterobonding, and its classification includes hydrogenated diamond-like carbon and hydrogen-free diamond-like carbon, with hydrogenated diamond-like carbon also containing carbon-hydrogen groups. Diamond-like carbon possesses excellent thermal conductivity and electrical insulation properties, and when introduced into an electrolyte as thermally conductive particles, it improves the temperature uniformity of the electrolyte, enhances the curing uniformity of the gel polymer matrix during the in-situ polymerization reaction process, is advantageous in improving the uniformity of the impedance and elastic modulus of the gel polymer electrolyte matrix and the dynamic performance of the battery, and is less likely to increase the probability of battery self-discharge problems. The characteristic peaks of carbon differ depending on the type of carbon material. In practice, a battery is disassembled, solid thermally conductive particles are collected from the gel polymer electrolyte, and an XRD test is performed on the resulting solid particle sample. The presence of diamond-like carbon can be determined based on the characteristic carbon peaks in the XRD pattern. For example, the solid particle sample can be placed on the XRD sample stage and measured using an XRD device with a Cu target as the X-ray source. If the sample shows diffraction peaks in the range of 2θ = 43°~45° and 74°~76°, it means that the solid particle sample contains characteristic diffraction peaks of diamond-like carbon, and that diamond-like carbon material is present in the electrolyte of the gel polymer electrolyte. To make it clear, the thermally conductive particles may consist solely of diamond-like carbon, or they may consist of both diamond-like carbon and other thermally conductive material particles that satisfy the thermal conductivity and electrical conductivity of the thermally conductive particles. Furthermore, the diamond-like carbon in the thermally conductive particles may consist of hydrogenated diamond-like carbon and / or hydrogen-free diamond-like carbon, and hydrogenated diamond-like carbon and hydrogen-free diamond-like carbon may each independently consist of one or more different types of diamond-like carbon. Selectively, the thermally conductive particles may consist solely of diamond-like carbon.

[0058] By using thermally conductive particles containing diamond-like carbon, it is possible to give these particles a high thermal conductivity and low electrical conductivity. This is advantageous in improving the uniformity of curing during the in-situ polymerization reaction of the polymer matrix, reducing the probability of self-discharge problems occurring in batteries, and thus improving the dynamic performance of batteries.

[0059] In some embodiments of this application, the atomic percentage of hydrogen in diamond-like carbon is 50 at% or less, selectively 20 at% or less, and even more selectively 10 at% or less, based on the total number of atoms in diamond-like carbon.

[0060] For example, the atomic percentage of hydrogen in diamond-like carbon may be 50 at%, 45 at%, 40 at%, 35 at%, 30 at%, 25 at%, 20 at%, 15 at%, 10 at%, 5 at%, 3 at%, etc., or it may be within a range of any of the above values. Here, the total number of atoms in diamond-like carbon can be understood as the sum of the moles of all elements contained in diamond-like carbon. For example, if diamond-like carbon contains only hydrogen and carbon, and the total number of moles of hydrogen is n1 and the total number of moles of carbon is n2, then the total number of atoms in diamond-like carbon will be n1 + n2, and the atomic percentage of hydrogen in diamond-like carbon will be n1 / (n1 + n2) × 100%. In actual operation, solid particles in the electrolyte of a gel polymer electrolyte can be collected and subjected to XRD testing. If only characteristic peaks of diamond-like carbon are found in the solid particle sample, it means that the solid particles are diamond-like carbon material. In this case, the solid particle sample can be sent to an elemental analyzer, completely combusted and decomposed in an environment with a small amount of pure oxygen, and the hydrogen content of the diamond-like carbon can be determined by quantitative analysis of the CO2 and H2O produced by the combustion. The lower the hydrogen content of the diamond-like carbon, the closer its performance becomes to that of diamond, with good thermal conductivity and electrical insulation. Using it as a thermally conductive particle in the electrolyte can further contribute to improving the uniformity of curing of the polymer matrix during the in-situ polymerization reaction process, and also reduce the probability of battery self-discharge problems. It should be noted that the diamond-like carbon may contain only hydrogenated diamond-like carbon, or it may contain both hydrogenated diamond-like carbon and hydrogen-free diamond-like carbon, as long as its hydrogen content meets the requirements of a predetermined range. To further improve the thermal conductivity and electrical insulation properties of the thermally conductive particles, the hydrogen content in the diamond-like carbon is selectively reduced to 20 at% or less, or 10 at% or less.

[0061] By controlling the hydrogen content in diamond-like carbon within a predetermined range, it is advantageous to improve the curing uniformity of the polymer matrix during the in-situ polymerization reaction process, and also to reduce the probability of battery self-discharge problems occurring, thereby improving the kinetic performance of the battery.

[0062] In some embodiments of this application, the total number of carbon atoms in diamond-like carbon is used as the basis for the sp in diamond-like carbon. 3 The atomic percentage of bonded carbon may be between 20 at% and 85 at%, and selectively between 70 at% and 85 at%.

[0063] For example, sp in diamond-like carbon 3 The atomic percentage of bonded carbon may be 20at%, 25at%, 30at%, 35at%, 40at%, 45at%, 50at%, 55at%, 60at%, 65at%, 70at%, 75at%, 80at%, 85at%, etc., or may be within a range of any of the above values. Here, the total number of carbon atoms in diamond-like carbon can be understood as the total number of moles of carbon elements in diamond-like carbon. In actual operation, solid particles in the electrolyte of a gel polymer electrolyte can be collected and an XRD test can be performed. If only the characteristic peak of diamond-like carbon is found in the solid particle sample, it means that the solid particles are diamond-like carbon material. At this time, an XPS test can be performed on the solid particle sample, and the sp² of carbon atoms can be determined by the XPS test of the carbon element. 2 and sp 3 Different characteristic peaks contributed by the different binding energies of the mixture were measured, at 284.4 eV and 285.2 eV, respectively. By splitting the XPS measurement peaks, the corresponding area ratios of the characteristic peaks at 284.4 eV and 285.2 eV were used to determine the sp 3 The proportion of bonded carbon can be determined. sp in diamond-like carbon 3The higher the content of bonded carbon, the closer its performance becomes to that of diamond, and its thermal conductivity and electrical insulation properties also improve. Using it as a thermal conductive particle in the electrolyte can further contribute to improving the uniformity of curing of the polymer matrix during the in-situ polymerization reaction process, and also reduce the probability of self-discharge problems occurring in batteries. However, sp 3 As the content of bonded carbon increases, the difficulty and cost of manufacturing also increase. It should be noted that the diamond-like carbon has a high sp 3 As long as the content of bound carbon meets the requirements within a predetermined range, it may contain only hydrogenated diamond-like carbon, or it may contain both hydrogenated diamond-like carbon and hydrogen-free diamond-like carbon. To further improve the thermal conductivity and electrical insulation of the thermally conductive particles, selectively, sp(s) of diamond-like carbon may be used. 3 The atomic percentage of bonded carbon should be set to 70 at% to 85 at%.

[0064] sp in diamond-like carbon 3 By controlling the content of bound carbon within a predetermined range, it is advantageous to improve the uniformity of curing of the polymer matrix during the in-situ polymerization reaction process, reduce the probability of battery self-discharge problems, improve the kinetic performance of the battery, and balance the difficulty and cost of manufacturing diamond-like carbon.

[0065] In some embodiments of this application, the particle size of the thermally conductive particles may be 10 μm or less.

[0066] For example, the particle size of the thermally conductive particles may be 10 μm or less, 8 μm or less, 6 μm or less, 4 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 100 nm or less, 50 nm or less, or within a range of any of the above values. The particle size of the thermally conductive particles can be measured using a laser particle size analyzer (e.g., Malvern Master Size 3000) with reference to the standard GB / T 19077.1-2016. The particle size of the thermally conductive particles affects the uniformity of their dispersion in the electrolyte and the transport pathway of active ions (e.g., lithium ions), which can affect the electrochemical performance of the battery. Selectively, the particle size of the thermally conductive particles may be 50 nm to 10 μm, and more selectively, the thermally conductive particles may include primary particles with a particle size of 5 nm to 1 μm and secondary particles with a particle size of 50 nm to 10 μm. The secondary particles can be formed by the aggregation of primary particles, and thermally conductive particles with smaller particle sizes may aggregate in the electrolyte. Controlling the particle sizes of the primary and secondary particles to satisfy a predetermined range is advantageous in improving the uniformity of dispersion of thermally conductive particles in the electrolyte and obtaining a better active ion transport effect.

[0067] By controlling the particle size of the thermally conductive particles within a predetermined range, it is advantageous to improve the temperature uniformity of the electrolyte and enhance the curing uniformity of the gel polymer matrix, as well as to give the battery good electrochemical performance.

[0068] In some embodiments of this application, the mass percentage of thermally conductive particles relative to the total mass of the gel polymer electrolyte may be 0.1 wt% to 5 wt%, and selectively 0.5 wt% to 2 wt%.

[0069] For example, relative to the total mass of the gel polymer electrolyte, the mass percentage of thermally conductive particles may be 0.1wt%, 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, etc., or may be within a range of any of the above values. Selectively, the thermally conductive particles in the electrolyte may be diamond-like carbon. The content of diamond-like carbon in the gel polymer electrolyte can be determined by TG-MS (thermogravimetric-mass spectrometry). Diamond-like carbon has an extremely high thermal stability temperature and good thermal conductivity, thus preventing localized overheating. The TG-MS test may involve separating the electrolyte and gel polymer matrix in the gel polymer electrolyte, filtering and washing to obtain a solid sample, heating the solid sample to 500°C for 20°C in an oxygen gas atmosphere to completely remove any residual components of the polymer electrolyte matrix that may be present, leaving only the diamond-like carbon components. The mass ratio of diamond-like carbon thermally conductive particles can be obtained from the masses of other components measured by TG-MS and the total mass of the gel polymer electrolyte sample. Increasing the mass concentration of thermally conductive particles in the gel polymer electrolyte is advantageous in improving the temperature uniformity of the electrolyte. However, if the concentration of thermally conductive particles in the electrolyte is too high, it may affect the transport pathway of active ions (e.g., lithium ions) to some extent.

[0070] By controlling the mass concentration of thermally conductive particles in the gel polymer electrolyte within a predetermined range, it is advantageous to improve the effect of thermally conductive particles on the curing uniformity of the gel polymer matrix, and also advantageous to obtain a better active ion transport effect.

[0071] In some embodiments of this application, the gel polymer electrolyte further comprises a gel polymer matrix, the gel polymer matrix may contain dispersed thermally conductive particles.

[0072] A gel polymer electrolyte comprises a gel polymer matrix and an electrolyte solution, the gel polymer matrix being a three-dimensional network structure formed by crosslinking and curing, the pores of which are filled with the electrolyte solution, and during in-situ curing of the gel polymer matrix or during the battery's charge-discharge cycle process, some thermally conductive particles may adhere to the gel polymer matrix. Here, the thermally conductive particles may include diamond-like carbon, and the presence of diamond-like carbon scattered on the gel polymer matrix can be confirmed by one or more conventional methods such as TG-MS testing, thermogravimetric analysis, and XRD testing.

[0073] By utilizing the property that thermally conductive particles may be scattered on the gel polymer matrix, it is possible to further confirm whether thermally conductive particles are present in the gel polymer electrolyte.

[0074] To make it understandable, the electrolyte of a Gegel polymer electrolyte may contain a solvent and an activated metal salt (for example, in the case of a lithium battery, the activated metal salt may be a lithium salt), the solvent may be a non-aqueous solvent, and selectively the solvent may include a main solvent and an auxiliary solvent, where the function of the main solvent may include dissolving the lithium salt and improving the electrochemical stability of the electrolyte, and the function of the auxiliary solvent may include reducing the viscosity of the electrolyte and further improving the ionic conductivity. Here, the types of solubilizers, auxiliary solvents and lithium salts are not particularly limited and can be flexibly selected according to the actual needs of those skilled in the art.

[0075] In some embodiments of this application, the main solvent in the electrolyte may include, but is not limited to, at least one of ester solvents, ether solvents, sulfone solvents, nitrile solvents, and ionic liquid solvents. Here, the ester solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), ethylene sulfite (ES), propylene sulfite (PS), dimethyl sulfite (DMS), diethyl sulfite (DES), γ-butyrolactone (BL), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), methyl formate (MF), ethyl formate (EF), methyl acetate (MA), ethyl acetate (EA), ethyl propionate (EP), ethyl butyrate (EB), and their fluoro derivatives. The ether-based solvent may include, but is not limited to, at least one of the following: dimethoxymethane (DMM), ethylene glycol dimethyl ether (DME), ethylene glycol diethyl ether (DEE), 1,2-dimethoxypropane (DMP), diethylene glycol dimethyl ether (DGM), tetrahydrofuran (THF), tetrahydropyran (THP), 1,3-dioxolane (DOL), 1,3-dioxane (1,3-DXA), 1,4-dioxane (1,4-DXA), and their fluoro derivatives. The sulfone-based solvent may include, but is not limited to, at least one of the following: dimethyl sulfone, dimethyl sulfoxide, sulfolane, ethyl methyl sulfone, tetramethylene sulfoxide, ethyl methyl sulfoxide, diethyl sulfone, diethyl sulfoxide, methylphenyl sulfone, methylphenyl sulfoxide, ethylphenyl sulfone, ethylphenyl sulfoxide, vinylphenyl sulfone, vinylphenyl sulfoxide, and their fluoro derivatives. Using a main solvent within the specified range described above is advantageous in promoting the dissolution of activated metal salts and providing the electrolyte with good ion transport properties.

[0076] In some embodiments of this application, the auxiliary solvent in the electrolyte may be a solvent that does not dissolve the activated metal salt and is well miscible with the main solvent. Generally, electrolytes with a low concentration of activated metal salt have low viscosity and high electrical conductivity, but somewhat poor electrochemical stability, while electrolytes with a high concentration have most solvent molecules that are activated metal ions (e.g., Li + Because it can combine with ) to form a solvated shell structure, it has high electrochemical stability, but the high viscosity and low ion mobility due to high concentration degrade the electrical performance of the electrolyte. By considering the aforementioned auxiliary solvent, which does not dissolve the activated metal salt but is well miscible with the main solvent, as a diluent, and adding the diluent to the high-concentration electrolyte to form a locally high-concentration electrolyte, the properties of the high-concentration electrolyte can be maintained, and the advantages of low viscosity and high ionic conductivity of the low-concentration electrolyte can be obtained. In other words, the electrolyte can be made to have the advantages of both low-concentration and high-concentration electrolytes, achieving both a relatively high ion transfer rate and relatively good electrochemical stability, thereby further improving the dynamic performance of the battery.

[0077] In some embodiments of this application, the auxiliary solvent in the electrolyte is fluoroethylene carbonate, cyclohexane, benzene, toluene, p-xylene, m-xylene, o-xylene, fluorobenzene, p-difluorobenzene, m-difluorobenzene, o-difluorobenzene, trifluorotoluene, trifluoromethoxybenzene, decafluoropentane, perfluoropentanone, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane, bis(2,2,2-trifluoroethyl) ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1H,1H,5H-octafluoro It may contain, but is not limited to, at least one of lopentyl-1,1,2,2-tetrafluoroethyl ether, ethyl trifluoromethyl ether, difluoromethyl-2,2,3,3,3-pentafluoropropyl ether, heptafluoropropyl-1,2,2,2-tetrafluoroethyl ether, difluoromethyl 2,2,3,3-tetrafluoropropyl ether, perfluoroisopropyl methyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, ethyl-1,1,2,2-tetrafluoroethyl ether, ethyl-2,2,2-tetrafluoroethyl ether, bis(1,1,2,2-tetrafluoroethyl) ether, etc. Selectively, the auxiliary solvent in the electrolyte may include at least one of trifluoromethoxybenzene, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, and 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane. Auxiliary solvents within a given range have a high electrochemical window, good compatibility, and excellent ability to promote the formation of fluorine-rich SEI. When combined with the main solvent, they can improve the ionic conductivity and electrochemical stability of the electrolyte and are also advantageous in reducing side reactions between the electrolyte and the negative electrode sheet.

[0078] In some embodiments of this application, the type of activated metal salt can be selected based on the type of battery to which the gel polymer electrolyte is applicable. For example, in a lithium battery, the activated metal salt may be a lithium salt, and the lithium salt in the electrolyte may be lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiOTF), difluoro The lithium salt may contain one or more of the following: lithium ionate (LiDFP), lithium dioxalatoborate (LiBOB), lithium difluorooxalatoborate (LiDFOB), lithium difluorobis(oxalato)phosphate, and lithium hexafluorophosphate. However, it is not limited to these, and for example, lithium bis(fluorosulfonyl)imide may be selected. The lithium salt decomposes on the negative electrode surface of the battery to form an inorganic fluorine-rich SEI component, and along with its relatively high dissociation ability, it is advantageous in achieving high electrolyte ionic conductivity and low electrolyte viscosity, thereby improving the electrochemical performance of the battery.

[0079] In some embodiments of this application, a gel polymer matrix can be formed by dispersing polymerizable monomers and / or prepolymers, initiators and activated metal salts, and thermally conductive particles of a gel polymer matrix together in an electrolyte, and then heating the electrolyte for polymerization after pouring it into a case containing an electrode assembly, thereby causing an in-situ polymerization reaction of the polymerizable monomers and / or prepolymers. Here, the initiator is used to initiate the polymerization of the polymerizable monomers and / or prepolymers to form the gel polymer matrix. Selectively, additives may be added to the electrolyte according to the actual needs to obtain the desired effect, for example, additives that suppress the dissolution of transition metals and / or additives that promote film formation. Here, the additive that promotes film formation may include, but is not limited to, at least one of propanesultone, ethylene sulfate, ethylene sulfite, tris(trimethylsilane) phosphate, tris(trimethylsilane) phosphite, tris(trifluoroethyl) phosphate, tris(trifluoroethyl) phosphite, tris(trimethylsilane) borate, dimethyl maleic anhydride, and 1,4-diisocyanatobutane. Selecting an additive within a predetermined range is advantageous in improving the stability of the positive and negative electrodes of the battery and extending the battery's service life.

[0080] A second aspect of this application provides a battery comprising a gel polymer electrolyte according to the first aspect of this application. The battery of this application has the features and effects described for the gel polymer electrolyte according to the first aspect of this application. In short, the battery has excellent kinetic performance. Selectively, the battery may be a rechargeable battery, for example, a lithium metal rechargeable battery or a lithium-ion battery.

[0081] In some embodiments of this application, the battery may further include a positive electrode sheet, a negative electrode sheet, and a separator, and at least one of the positive electrode sheet, negative electrode sheet, and separator may contain thermally conductive particles.

[0082] The gel polymer electrolyte is distributed between the sheet and the separator. By distributing thermally conductive particles in at least one of the positive electrode sheet, negative electrode sheet, and separator, the uniformity of the positive electrode sheet, negative electrode sheet, and separator is improved, thereby improving the temperature uniformity of the electrolyte and contributing to an improved effect on the curing uniformity of the polymer matrix during the in-situ polymerization reaction. Selectively, the thermally conductive particles may include diamond-like carbon. XRD testing can be used to determine whether diamond-like carbon is present in the positive electrode sheet, negative electrode sheet, or separator. For example, the battery can be disassembled to obtain the positive electrode sheet, negative electrode sheet, or separator. Taking the positive electrode sheet or negative electrode sheet as an example, after cleaning, the surface material (e.g., the active material layer) on the sheet is scraped off to form a powder. An XRD test is then performed on the powder sample, and based on the characteristic peaks in the XRD test pattern, it can be determined whether thermally conductive particles are present in the sheet. For specific procedures and determination methods, please refer to the explanation in the previous section. It should be noted that silicon and other commonly used carbon-containing anode active materials do not exhibit the diffraction peak at the corresponding peak position of diamond-like carbon.

[0083] The distribution of thermally conductive particles on at least one of the positive electrode sheet, negative electrode sheet, and separator is advantageous in further improving the temperature uniformity of the electrolyte and improving the curing uniformity of the polymer matrix during the in-situ polymerization reaction.

[0084] In some embodiments of this application, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on the positive electrode current collector, and the positive electrode active material layer may contain thermally conductive particles.

[0085] For example, the thermally conductive particles may be scattered within the positive electrode active material layer. Alternatively, the thermally conductive particles can be selectively dispersed in an activated slurry of the positive electrode active material layer, and the activated slurry can be applied to at least one layer of the positive electrode current collector to obtain a positive electrode active material layer containing thermally conductive particles. In a battery, the positive electrode active material layer can be in direct contact with the electrolyte. Placing thermally conductive particles in the positive electrode active material layer further improves the temperature uniformity of the electrolyte, which is advantageous in improving the curing uniformity of the polymer matrix during the in-situ polymerization reaction process. It is also advantageous in improving the heat dissipation effect of the battery during use and reducing the probability of heat concentration occurring inside the battery.

[0086] By incorporating thermally conductive particles into the positive electrode active material layer, it is advantageous to further improve the uniformity of the curing of the polymer matrix during the in-situ polymerization reaction process, and also to improve the heat dissipation effect and temperature uniformity during battery use.

[0087] In some embodiments of this application, the positive electrode current collector may be a conventional metal foil sheet or a composite current collector (a composite current collector may be formed by placing a metal material on a polymer substrate). For example, the positive electrode current collector may be aluminum foil. The positive electrode active material layer includes a positive electrode active material, where the specific type of positive electrode active material is not limited, and any known active material in the art that can be used in the positive electrode of a battery may be used, and a person skilled in the art can select it according to the actual needs. For example, in the case of a lithium battery, the positive electrode active material includes, but is not limited to, a lithium transition metal oxide and / or a lithium-containing phosphate with an olivine structure. The lithium transition metal oxide may include lithium transition metal oxides that are not coated and / or selectively coated and modified, and the lithium phosphate with an olivine structure may include lithium-containing phosphates with an olivine structure that are not coated and / or selectively coated and modified. Some specific examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiLiLi 0.5 Co 0.2 Mn 0.3 O2, LiLiLi 0.5 Co 0.25 Mn 0.25 O2, LiLiLi 0.6 Co 0.2 Mn 0.2 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2, LiLiLi 0.96 Co 0.02 Mn 0.02O2, etc.), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 The material may include, but is not limited to, at least one of the following: O2 (and other similar substances) and their modified compounds. Some specific examples of lithium-containing phosphates with an olivine structure include, but are not limited to, at least one of the following: lithium iron phosphate (e.g., LiFePO4), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Cathode active materials within a given range may be prepared or obtained commercially.

[0088] In some specific embodiments of this application, the positive electrode active material layer may further selectively contain an adhesive, a conductive agent, and other selective additives. For example, the conductive agent may include, but is not limited to, one or more of acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, Super P (SP), graphene, and carbon nanofibers. For example, the adhesive may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0089] In some embodiments of this application, the mass ratio of thermally conductive particles in the positive electrode active material layer may be 0.1 wt% to 2 wt%.

[0090] For example, the mass percentage of thermally conductive particles in the positive electrode active material layer may be 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, 0.9wt%, 1.1wt%, 1.3wt%, 1.5wt%, 1.7wt%, 1.9wt%, 2wt%, etc., or it may be within a range of any of the above values. To measure the content of thermally conductive particles in the positive electrode active material layer, first, the battery is disassembled to obtain the positive electrode sheet. After cleaning, the positive electrode active material layer on the positive electrode sheet is scraped off, its weight is measured, and an excess hydrochloric acid solution is added to completely dissolve the positive electrode active material in the positive electrode active material layer, leaving the adhesive, thermally conductive particles, and conductive agent. Next, the remaining material is washed with N-methylpyrrolidone (NMP) until the adhesive is completely removed, and then dried to obtain a powder mixture of conductive agent and thermally conductive particles. The components of the powder mixture are confirmed by conventional methods such as XRD testing, and the content of thermally conductive particles is confirmed in combination with TG-MS testing based on the difference in decomposition temperatures between the thermally conductive particles and the conductive agent, thereby obtaining the content of thermally conductive particles in the positive electrode active material layer. For example, if we assume that the thermally conductive particles and conductive agent in the powder mixture are diamond-like carbon and carbon black, respectively, then the powder mixture can be loaded into a TG-MS and a thermogravimetric analysis can be performed. The mixture is heated to 550°C at a rate of 20°C / min in an oxygen gas atmosphere, held for 30 minutes to completely decompose the carbon black, and the mass ratio of the conductive agent is confirmed. The temperature is then raised to over 800°C, and the mass of the diamond-like carbon is measured to confirm the mass ratio of diamond-like carbon in the positive electrode active material layer. Here, increasing the mass ratio of thermally conductive particles in the positive electrode active material layer is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery. However, as the content of thermally conductive particles in the positive electrode active material layer increases, the relative content of the positive electrode active material in the positive electrode sheet decreases, and the conductivity of the positive electrode active material layer also decreases.

[0091] By controlling the mass ratio of thermally conductive particles in the positive electrode active material layer within a predetermined range, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and also to achieve both the conductivity of the positive electrode sheet and the energy density of the battery.

[0092] In some embodiments of this application, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector, and the negative electrode active material layer may contain thermally conductive particles; or the negative electrode sheet may include a negative electrode current collector and a thermal conductive layer provided on the negative electrode current collector, and the thermal conductive layer may contain thermally conductive particles.

[0093] In a battery, the negative electrode sheet generally includes a current collector and a negative electrode active material layer. When the negative electrode sheet includes a negative electrode active material layer, the negative electrode active material layer includes the negative electrode active material. The negative electrode current collector may be a conventional metal foil sheet or a composite current collector (for example, a composite current collector may be formed by placing a metal material on a polymer substrate). As an example, the negative electrode current collector may be copper foil. In this case, thermally conductive particles may be scattered within the negative electrode active material layer.

[0094] Furthermore, the negative electrode sheet does not necessarily contain a negative electrode active material layer. In this case, the negative electrode current collector may be a metal current collector. The metal current collector may include, but is not limited to, a single metal. For example, in the case of a lithium battery, the material of the negative electrode current collector may be metallic lithium, or an alloy of metallic lithium with various other metals or non-metallic elements. Selectively, the metal elements may include, but are not limited to, tin (Sn), zinc (Zn), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), gallium (Ga), indium (In), foil (Pt), etc. Selectively, the non-metallic elements may include, but are not limited to, boron (B), carbon (C), silicon (Si), etc. As an example, the negative electrode current collector may be lithium foil. If the negative electrode sheet does not contain a negative electrode active material layer, during the cycle process, only the lithium in the positive electrode is used and deposits and peels off on the negative electrode side in the form of lithium metal. At this time, a thermal conductive layer may be placed on the surface of the negative electrode current collector, and the thermal conductive layer may contain thermal conductive particles. As can be understood, the thermal conductive layer may contain only thermal conductive particles or may contain other components, and these other components may include, but are not limited to, adhesives.

[0095] In batteries, the negative electrode sheet can be in direct contact with the electrolyte. Dispersing thermally conductive particles in the negative electrode active material layer, or installing a thermally conductive layer containing thermally conductive particles on the surface of the negative electrode sheet, further improves the temperature uniformity of the electrolyte. This is advantageous in improving the uniformity of curing of the polymer matrix during the in-situ polymerization reaction process. At the same time, it is advantageous in improving the heat dissipation effect of the battery during use and reducing the probability of heat concentration occurring inside the battery.

[0096] By placing thermally conductive particles in the negative electrode active material layer, or by placing a thermally conductive layer containing thermally conductive particles on the surface of the negative electrode sheet, it is advantageous to further improve the curing uniformity of the polymer matrix during the in-situ polymerization reaction process, and also to improve the heat dissipation effect and temperature uniformity of the battery during use.

[0097] In some embodiments of this application, the negative electrode active material may include a silicon material, for example, a composite negative electrode active material doped with a silicon-based material and a carbon material, and using a silicon material in the negative electrode active material layer is advantageous for further improving the energy density of the battery.

[0098] In some embodiments of this application, the negative electrode active material layer may further selectively contain an adhesive, a conductive agent, and other selective additives. For example, the conductive agent may include, but is not limited to, one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. For example, the adhesive may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB). For example, other selective additives may include, but are not limited to, thickeners and dispersants (e.g., sodium carboxymethylcellulose CMC-Na) and PTC thermistor materials.

[0099] In some embodiments of this application, the mass ratio of thermally conductive particles in the negative electrode active material layer may be 0.1 wt% to 4 wt%.

[0100] For example, the mass ratio of thermally conductive particles in the negative electrode active material layer may be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, or within a range of any of the above values. Increasing the mass ratio of thermally conductive particles in the negative electrode active material layer is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery. However, as the content of thermally conductive particles in the negative electrode active material layer increases, the relative content of the negative electrode active material in the negative electrode sheet decreases, and the conductivity of the negative electrode active material layer also decreases.

[0101] By controlling the mass ratio of thermally conductive particles in the negative electrode active material layer within a predetermined range, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and also to achieve both the conductivity of the negative electrode sheet and the energy density of the battery.

[0102] In some embodiments of this application, the negative electrode active material layer may further contain silicon material, and the mass percentage of silicon element in the negative electrode active material layer may be 10 wt% or more.

[0103] For example, the mass percentage of silicon elements in the negative electrode active material layer may be 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, 30 wt% or more, 35 wt% or more, or within a range consisting of any of the above values. Silicon has a high theoretical specific capacity and a low lithium insertion potential, and using silicon material as the negative electrode active material is advantageous for further improving the energy density of the negative electrode sheet and the battery. Selectively, silicon material and carbon material may be composited as the negative electrode active material. Also selectively, the negative electrode active material layer may contain both silicon material and thermally conductive particles, and since silicon material has relatively low thermal conductivity, using both silicon material and thermally conductive particles in the negative electrode active material layer is advantageous for improving both the charge-discharge ratio capacity and thermal conductivity uniformity of the negative electrode sheet.

[0104] Controlling the mass ratio of silicon elements in the negative electrode active material layer within a predetermined range is advantageous for improving the energy density of the negative electrode sheet and the battery.

[0105] In some embodiments of this application, the thickness of the thermal conductive layer may be 50 nm to 5 μm.

[0106] When a thermal conductive layer is installed on the negative electrode current collector, the thickness of the thermal conductive layer may be 50 nm, 60 nm, 70 nm, 80 nm, 100 nm, 200 nm, 500 nm, 800 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or within a range of any of the above values. When measuring the thickness of the thermal conductive layer, a cross-section of the negative electrode sheet is prepared by freeze-ion beam polishing (Cryo-CP), and observed with a scanning electron microscope (SEM). It is found that the average particle size of the thermal conductive particles in the thermal conductive layer is lower than that of the negative electrode layer active material, thereby allowing the spatial distribution of the thermal conductive layer to be identified and its thickness measured by SEM. By selectively forming a thermal conductive layer on the surface of the negative electrode current collector using vapor deposition and adjusting the vapor deposition, a porous structure can be given to the thermal conductive layer. A thermal conductive layer with a porous structure is advantageous for improving the uniform deposition of active ions on the surface of the negative electrode sheet of the battery and for improving effective contact between the negative electrode sheet and the electrolyte. Increasing the thickness of the thermal conductive layer is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery. However, as the thickness of the thermal conductive layer increases, the energy density of the battery may decrease, and the conductivity of the negative electrode sheet may also decrease.

[0107] By controlling the thickness of the thermal conductive layer within a predetermined range, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and also to achieve both the conductivity of the negative electrode sheet and the energy density of the battery.

[0108] In some embodiments of this application, the mass ratio of thermally conductive particles in the thermally conductive layer may be 50 wt% or more.

[0109] When a thermal conductive layer is provided on the negative electrode current collector, the mass ratio of thermal conductive particles in the thermal conductive layer may be 50 wt% or more, 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, 75 wt% or more, or within a range consisting of any of the above values. The mass ratio of thermal conductive particles in the thermal conductive layer can be measured by scraping off the thermal conductive layer, removing other components in the thermal conductive layer using conventional methods such as solvent methods and / or ultrasonic methods, and comparing the weight change of the sample before and after the removal of other components. Increasing the mass ratio of thermal conductive particles in the thermal conductive layer is advantageous for further improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, but it may reduce the electrical conductivity of the thermal conductive layer and the negative electrode sheet.

[0110] By controlling the content of thermally conductive particles in the thermal conductive layer within a predetermined range, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and it is also advantageous to consider the conductivity of the negative electrode sheet.

[0111] In some embodiments of this application, the thermal conductive layer further comprises a conductive agent and / or an adhesive, wherein the mass percentage of the conductive agent in the thermal conductive layer may be 0.1 wt% to 40 wt%, selectively 5 wt% to 15 wt%, and the mass percentage of the adhesive in the thermal conductive layer may be 0.01 wt% to 5 wt%.

[0112] For example, the mass percentage of the conductive agent in the thermal conductive layer may be 0.1wt%, 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, etc., or may be within a range of any of the above values. The mass percentage of the adhesive in the thermal conductive layer may be 0.01wt%, 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, etc., or may be within a range of any of the above values. To measure the adhesive content in a thermal conductive layer, the thermal conductive layer is scraped off, ground into powder, weighed, and then washed with N-methylpyrrolidone and deionized water, respectively, until the adhesive is sufficiently dissolved. After thoroughly drying the powder, it is weighed again, and the difference between these two weight measurements represents the mass percentage of adhesive in the thermal conductive layer. If the thermal conductive layer also contains a conductive agent, the thermal conductive particles and the conductive agent can be separated by combining this method with conventional methods such as ultrasonic methods. For example, if the conductive agent is conductive carbon black and the thermal conductive particles are diamond-like carbon, and the density of the diamond-like carbon is 3 g / cm³, then... 3 It is ultra-high, and the density of conductive carbon black is 3 g / cm³. 3 Based on the characteristic of being less than 3 g / cm³, a mixture powder of conductive agent and thermally conductive particles was created with a density of 3 g / cm³. 3 The particles are ultrasonically treated in a solvent, and after ultrasonic treatment, the particles are dispersed and form layers in the solvent. The conductive portion of the upper layer is taken, dried, and weighed, thereby allowing the mass percentage of the conductive material in the thermal conductive layer to be determined. Selectively, the mass percentage of thermal conductive particles in the thermal conductive layer can be obtained by further measuring the thermal conductive particle portion of the lower layer, drying, and weighing, and / or by referring to the mass percentage of the conductive material and / or adhesive.

[0113] Because thermally conductive particles have low electrical conductivity, it is possible to improve the conductivity of the negative electrode sheet by incorporating an appropriate amount of conductive agent into the thermal conductive layer, or to improve the adhesion of the thermal conductive layer to the surface of the negative electrode current collector by incorporating an appropriate amount of adhesive into the thermal conductive layer. However, the amount of each added will have a slight effect on the thermal conductivity of the thermal conductive layer.

[0114] By controlling the content of conductive agents and / or adhesives in the thermal conductive layer within a predetermined range, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and it is also advantageous to achieve both the conductivity of the negative electrode sheet and the adhesion strength of the conductive layer.

[0115] In some embodiments of this application, the mass ratio of thermally conductive particles in the electrolyte may be greater than or equal to the mass ratio of thermally conductive particles in the negative electrode active material layer.

[0116] As a specific example, thermally conductive particles can be dispersed in both the electrolyte and the negative electrode active material layer. Compared to dispersing the thermally conductive particles only in the negative electrode active material layer, dispersing them in the electrolyte is advantageous in improving the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, and it does not affect the amount of negative electrode active material in the negative electrode sheet.

[0117] By setting the mass ratio of thermally conductive particles in the electrolyte to be greater than or equal to the mass ratio of thermally conductive particles in the negative electrode active material layer, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the heat dissipation effect of the battery, as well as to consider the energy density of the battery.

[0118] In some embodiments of this application, the mass ratio of thermally conductive particles in the negative electrode active material layer may be greater than or equal to the mass ratio of thermally conductive particles in the positive electrode active material layer.

[0119] To improve the charge-discharge ratio capacity of the negative electrode sheet, the negative electrode active material may contain a silicon material with a low thermal conductivity coefficient. By increasing the content of thermally conductive particles in the negative electrode active material layer compared to the positive electrode active material layer, it is advantageous to improve the uniformity of thermal conduction of the negative electrode sheet and the consistency of the overall thermal conduction effect inside the battery, thereby improving the thermal conduction effect of the negative electrode sheet containing silicon material and the curing uniformity of the gel polymer matrix.

[0120] By making the mass ratio of thermally conductive particles in the negative electrode active material layer equal to or greater than the mass ratio of thermally conductive particles in the positive electrode active material layer, it is advantageous to further improve the curing uniformity of the gel polymer matrix and the effect of improving battery heat dissipation.

[0121] In some embodiments of this application, the battery may further include a separator, which may include, but is not limited to, a porous polyethylene membrane, a porous polypropylene membrane, a porous polyimide membrane, and a porous membrane formed by a composite of multiple polymers.

[0122] In some embodiments of this application, the shape of the battery of the second embodiment of this application is not particularly limited and can be flexibly selected according to the actual needs of those skilled in the art, and may be cylindrical, rectangular (see Figure 1 for understanding), or any other shape.

[0123] In some embodiments of this application, the battery may include an outer packaging for packaging a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte.

[0124] In some embodiments, the outer packaging may include a case and a cover plate. Here, the case may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and side plates surround each other to form a storage chamber. The case has an opening that communicates with the storage chamber, and the cover plate can cover the opening and seal the storage chamber.

[0125] In some embodiments, the positive electrode sheet, negative electrode sheet, and separator can be formed into an electrode assembly by a winding or lamination process. The electrode assembly is packaged in the containment chamber. The electrolyte in the gel polymer electrolyte permeates the electrode assembly. The number of electrode assemblies contained in the battery may be one or more and can be adjusted as needed.

[0126] In some embodiments, the battery's outer packaging may be a rigid case, which may be a metal case or a non-metallic case, such as a rigid plastic case, an aluminum case, or a steel case.

[0127] In some embodiments, the battery's outer packaging may be a soft pack, such as a bag-type soft pack. The material of the soft pack may include plastic, for example, one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS), or it may be, for example, an aluminum laminate film.

[0128] In some embodiments of this application, the battery may be a battery cell 1 (see Figure 1 for understanding), or a battery module 2 (see Figure 2 for understanding) or a battery pack 3 (see Figure 3 for understanding) consisting of a battery cell 1.

[0129] In some embodiments, the battery may be a battery module, and the number of battery cells contained in the battery module may be one or more, and the specific number can be adjusted according to the application and capacity of the battery module. Figure 2 shows an example of a battery module 2. Referring to Figure 2, in the battery module 2, a plurality of battery cells 1 may be arranged sequentially along the longitudinal direction of the battery module 2. Of course, they may be arranged according to any other method. Furthermore, the plurality of battery cells 1 may be secured by fastening members. Optionally, the battery module 2 may further include a housing having a housing space, and the plurality of battery cells 1 are housed in the housing space.

[0130] In some embodiments, the battery modules can be further assembled to form a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack. Referring to Figure 3 or 4 (Figures 3 and 4 show a battery pack 3 as an example), the battery pack 3 may include a battery box and a plurality of battery modules 2 installed in the battery box. The battery box may include an upper housing 4 and a lower housing 5, the upper housing 4 can cover the lower housing 5 and form a closed space for housing the battery modules 2. The plurality of battery modules 2 may be arranged in the battery box in any manner.

[0131] Furthermore, this application provides an electrical device which includes a battery according to a second embodiment of this application. The battery, for example, a battery cell, a battery module, or a battery pack, may serve as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobility devices (e.g., mobile phones, laptops), electric vehicles (e.g., 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. Referring to Figure 5, it is understood that, as a specific example, the electrical device may be a vehicle. The electrical device may select a specific type of battery according to its usage needs, for example, a battery cell, a battery module, or a battery pack.

[0132] For example, the electrical device may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. Battery packs or battery modules may be used to meet the high power and high energy density needs of the battery for the electrical device.

[0133] As another example, the electrical device may be a mobile phone, tablet, laptop, etc. Generally, there is a requirement for the electrical device to be thin and lightweight, and a battery core may be used as the power source.

[0134] Examples of the present application are described below. The examples described below are illustrative and are for interpretive purposes only, and should not be considered as limitations thereon. Unless otherwise specified in the examples, specific techniques or conditions shall be followed in accordance with the techniques or conditions described in the literature in the art or in accordance with product specifications. Unless otherwise specified, the reagents or instruments used are all common commercially available products.

[0135] Examples of the present application are described below. The examples described below are illustrative and are for interpretive purposes only, and should not be considered as limitations thereon. Unless otherwise specified in the examples, specific techniques or conditions shall be followed in accordance with the techniques or conditions described in the literature in the art or in accordance with product specifications. Unless otherwise specified, the reagents or instruments used are all common commercially available products.

[0136] Example 1

[0137] (1) Manufacturing of positive electrode sheets

[0138] Cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, conductive agent acetylene black, and adhesive PVDF (polyvinylidene fluoride) are mixed in a mass ratio of 96:2:2, and solvent N-methylpyrrolidone (NMP) is added. The mixture is stirred until the system is homogeneous to obtain a positive electrode slurry (solid content 40 wt%). This positive electrode slurry is then applied to both sides of the positive electrode current collector aluminum foil, with a solid content of approximately 20 mg / cm³. 2 The material is applied uniformly with a load of [specified amount], dried at room temperature, then transferred to an oven to continue drying, cut into 40mm x 50mm rectangles to form the positive electrode sheet, and the positive electrode area capacity is 4mAh / cm². 2 That is the case.

[0139] (2) Manufacturing of negative electrode sheets

[0140] A 20μm lithium foil was wound onto a 12μm copper foil using a roll press method, and then cut into a 41mm x 51mm rectangle to form the negative electrode sheet.

[0141] Alternatively, a negative electrode active material of 20 wt% Si-Graphite silicon carbon, a conductive agent of carbon nanotubes, and an adhesive of SBR (styrene-butadiene rubber) are mixed in a mass ratio of 96.9:0.1:3, solvent NMP is added, and the mixture is stirred until the system is homogeneous to obtain a negative electrode slurry (solid content 30 wt%), and the negative electrode slurry is applied to both sides of the copper foil of the negative electrode current collector with a solid content of approximately 3.9 mg / cm³. 2 The material was uniformly applied with a load of [specified amount], dried at room temperature, then transferred to an oven to continue drying, cut into 41mm x 51mm rectangles to form the positive electrode sheet, and the negative electrode area capacity was 4.4mAh / cm². 2 That is the case.

[0142] (3) Preparation of gel polymer electrolyte precursor solution:

[0143] 115 g of the main solvent (a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio), 6 g of the auxiliary solvent fluoroethylene carbonate (FEC), 15 g of the lithium salt LiPF6, and diamond-like carbon were mixed to form a 1 M electrolyte. Then, 20 g of the polymerizable monomer vinylene carbonate, 6.67 g of the crosslinking agent polyethylene glycol diacrylate, and 0.53 g of the initiator azobisisobutyronitrile were added. Here, the thermal conductivity of diamond-like carbon is 1000 W / mK, and the electrical conductivity is 3.9 × 10⁻⁶ -12 The ratio is S / cm, and the mass percentage in the gel polymer electrolyte precursor solution is 2 wt%.

[0144] (4) Manufacturing of separators

[0145] A 10μm thick porous polyethylene film was selected as the separator and cut into 45mm x 55mm rectangles in preparation for use.

[0146] (5) Manufacturing of secondary batteries

[0147] Battery assembly: Twelve cut positive electrode sheets were taken and combined with thirteen cut negative electrode sheets. The positive and negative electrodes were separated by the aforementioned separator, and the assembly was wrapped in an aluminum plastic film bag to form a stacked dry cell core. 4.5 g of the electrolyte prepared above was injected, and the aluminum plastic film bag was packaged using a vacuum hot press. After curing at 70°C for 6 hours, and then standing at room temperature for at least 12 hours, testing could be started. The rated capacity of the stacked battery thus fabricated is 2376 mAh.

[0148] Examples 2-20 and Comparative Example 1

[0149] The difference between Comparative Example 1 and Example 1 is that in step (3), diamond-like carbon is not added when preparing the gel polymer electrolyte precursor solution.

[0150] The difference between Examples 2-7 and Example 1 is that the thermal conductivity of the diamond-like carbon is different.

[0151] The difference between Examples 8-11 and Example 1 is that the mass ratio of diamond-like carbon in the gel polymer electrolyte is different.

[0152] The difference between Examples 12-14 and Example 1 is that the particle size range of the diamond-like carbon is different.

[0153] The difference between Examples 15-19 and Example 2 is the hydrogen content of the diamond-like carbon and sp. 3 The difference lies in the bonded carbon content, which results in different thermal and electrical conductivity.

[0154] The difference between Examples 20-24 and Example 2 is that the electrical conductivity and thermal conductivity of the diamond-like carbon are different. The thermal conductivity of the diamond-like carbon in Examples 20-24 at 25°C is greater than 400 W / mK in all cases.

[0155] Performance testing

[0156] The curing uniformity of the diamond-like carbon used in the above examples and comparative examples, and the gel polymer electrolyte of the fabricated secondary batteries, was tested. The test method included the following:

[0157] 1. Testing of the electrical conductivity and thermal conductivity coefficient of diamond-like carbon.

[0158] At room temperature and pressure, conduct an electrical conductivity test referring to the test method for volume electrical conductivity in GB / T 1410-2006.

[0159] Thermal conductivity tests were conducted at room temperature and atmospheric pressure, referring to GB / T 32064-2015.

[0160] 2. Hydrogen content and sp of diamond-like carbon 3 Test of bonded carbon content

[0161] The hydrogen content in diamond-like carbon was determined by completely burning and decomposing the carbon and quantitatively analyzing the CO2 and H2O produced by the combustion.

[0162] By performing XPS testing on diamond-like carbon, the splines of carbon atoms can be determined. 2 and sp 3 Different characteristic peaks contributed by the different binding energies of the mixture were measured, at 284.4 eV and 285.2 eV, respectively. By splitting the XPS test peaks, the corresponding area ratios of the characteristic peaks at 284.4 eV and 285.2 eV were used to determine the sp 3 The proportion of bonded carbon can be determined.

[0163] 3. Test for curing uniformity of gel polymer electrolytes

[0164] The fabricated battery core was disassembled, the separator containing the hardened gel polymer electrolyte was removed, the separator was placed on a stainless steel plate, and the stainless steel was connected to the counter electrode of the electrochemical mode of an atomic force microscope to form a test path. Using the atomic force microscope, a 10x10 dot matrix could be used to set up test points on a separator area of ​​5cm x 5cm, and the elastic modulus E of each test point was determined by atomic force microscopy testing in mechanical mode. i By obtaining this, and simultaneously conducting an impedance test of the electrochemical mode, the AC impedance Z at each test point was determined. i The curing uniformity of the gel polymer electrolyte was evaluated based on the elastic modulus and AC impedance measured at each test point, where the uniformity of the distribution of the elastic modulus A E and the uniformity of the distribution of electrochemical impedance A Z These were evaluated using the following formulas:

number

number

[0165] 4. Testing of ionic conductivity and electronic conductivity of gel polymer electrolytes.

[0166] The battery core was disassembled, the gel polymer electrolyte membrane was removed, and the ionic and electronic conductivity of the gel polymer electrolyte membrane was tested. The ionic conductivity test method was carried out in accordance with standard HG / T 4067-2015. The resistance of the gel polymer electrolyte was tested using an electrical conductivity meter under constant temperature of 25±0.1℃ and AC impedance conditions of 1kHz, and its electrical conductivity was calculated accordingly. For the electronic conductivity of the gel polymer electrolyte, the resistance value measured by the DC double probe method was used, where the contact area between the probe and the gel polymer electrolyte membrane was 49πmm². 2The settings may be adjusted as follows: For example, the resistance R of a gel polymer electrolyte membrane can be tested using a HIOKI BT23562 internal resistance tester. The specific procedure is as follows: the upper and lower sides of the gel polymer electrolyte membrane sheet are sandwiched between the two conductive terminals of the tester, pressure is applied to fix it in place, the diameter of the conductive terminals is 14 mm, and the applied pressure is 15 MPa to 27 MPa. The resistance R of the gel polymer electrolyte membrane is measured, and the electronic conductivity σ of the gel polymer electrolyte is calculated based on the formula σ = d / S × (1 / R), where S is the detection area, and in this test, the detection area is equal to the area of ​​the conductive terminals, and d is the thickness of the test sample between the two conductive terminals, i.e., the thickness of the gel polymer electrolyte membrane.

[0167] Table 1 shows the test results for Examples 1-24 and Comparative Example 1.

[0168] Table 1 Differences and test results of Examples 1-14 and Comparative Example 1

[0169] [Table 1]

[0170] Table 2 Differences and test results of Examples 2, 15-19

[0171] [Table 2]

[0172] Table 3 Differences and test results of Examples 2, 20-24

[0173] [Table 3]

[0174] Results and conclusions:

[0175] As can be seen from Examples 1-24 and Comparative Example 1, dispersing diamond-like carbon as thermally conductive particles in the electrolyte of a gel polymer electrolyte is advantageous in improving the curing uniformity of the gel polymer matrix during the in-situ curing process. Furthermore, the amount of diamond-like carbon added to the gel polymer electrolyte, and the thermal conductivity, hydrogen content, and sp of the diamond-like carbon are all relevant factors. 3 Changes in the bonded carbon content and particle size all have a certain effect on improving the curing uniformity of the gel polymer matrix during the in-situ curing process, and the improvement effect can be further enhanced by further optimizing the selection of each parameter.

[0176] Finally, it should be noted that the above embodiments are used solely to illustrate the technical solutions of this application and are not limiting. While this application is described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions described in the above embodiments can be modified, or some or all of their technical features can be replaced with equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of this application, and they should all be included within the scope of the claims and specification of this application. In particular, unless there is a structural inconsistency, each technical feature mentioned in each embodiment can be combined in any manner. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions included in the claims.

Claims

1. A gel polymer electrolyte comprising an electrolyte in which thermally conductive particles are dispersed, wherein the thermal conductivity coefficient of the thermally conductive particles at 25°C is 400 W / mK or higher.

2. The electrical conductivity of the aforementioned thermally conductive particles at 25°C is 10 －７ It is less than or equal to S / cm, and selectively, 10 －１６ S / cm ~ 10 －７ The gel polymer electrolyte according to claim 1, wherein the S / cm ratio is as described above.

3. The gel polymer electrolyte according to claim 1 or 2, wherein the thermal conductivity coefficient is 400 W / mK to 2000 W / mK.

4. The gel polymer electrolyte according to any one of claims 1 to 3, wherein the thermally conductive particles include diamond-like carbon.

5. Based on the total number of atoms in the diamond-like carbon, the atomic percentage of hydrogen in the diamond-like carbon is 50 at% or less, selectively 20 at% or less, more selectively 10 at% or less, and / or Based on the total number of carbon atoms in the diamond-like carbon, the sp in the diamond-like carbon ３ The gel polymer electrolyte according to claim 4, wherein the atomic percentage of bonded carbon is 20 at% to 85 at%, and selectively 70 at% to 85 at%.

6. The gel polymer electrolyte according to any one of claims 1 to 5, wherein the particle size of the thermally conductive particles is 10 μm or less.

7. The gel polymer electrolyte according to any one of claims 1 to 6, wherein the mass ratio of the thermally conductive particles is 0.1 wt% to 5 wt%, and selectively 0.5 wt% to 2 wt%, based on the total mass of the gel polymer electrolyte.

8. The gel polymer electrolyte according to any one of claims 1 to 7, further comprising a gel polymer matrix, wherein the thermally conductive particles are dispersed within the gel polymer matrix.

9. A battery comprising a gel polymer electrolyte according to any one of claims 1 to 8.

10. The battery according to claim 9, further comprising a positive electrode sheet, a negative electrode sheet, and a separator, wherein at least one of the positive electrode sheet, the negative electrode sheet, and the separator contains the thermally conductive particles.

11. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on the positive electrode current collector, wherein the positive electrode active material layer contains the thermally conductive particles and / or The battery according to claim 10, wherein the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector, and the negative electrode active material layer contains the thermally conductive particles, or the negative electrode sheet comprises a negative electrode current collector and a thermal conductive layer provided on the negative electrode current collector, and the thermal conductive layer contains the thermally conductive particles.

12. The battery according to claim 11, wherein the mass ratio of the thermally conductive particles in the positive electrode active material layer is 0.1 wt% to 2 wt%.

13. The battery according to claim 11 or 12, wherein the mass ratio of the thermally conductive particles in the negative electrode active material layer is 0.1 wt% to 4 wt%, and / or the negative electrode active material layer contains a silicon material, and the mass ratio of silicon elements in the negative electrode active material layer is 10 wt% or more.

14. The battery according to any one of claims 11 to 13, wherein the thickness of the thermal conductive layer is 50 nm to 5 μm, and / or the mass ratio of the thermal conductive particles in the thermal conductive layer is 50 wt% or more.

15. The battery according to any one of claims 11 to 14, wherein the thermal conductive layer further comprises a conductive agent and / or an adhesive, the mass ratio of the conductive agent in the thermal conductive layer is 0.1 wt% to 40 wt%, selectively 5 wt% to 15 wt%, and the mass ratio of the adhesive in the thermal conductive layer is 0.01 wt% to 5 wt%.

16. The battery according to any one of claims 11 to 15, wherein the mass ratio of the thermally conductive particles in the electrolyte is equal to or greater than the mass ratio of the thermally conductive particles in the negative electrode active material layer, and / or the mass ratio of the thermally conductive particles in the negative electrode active material layer is equal to or greater than the mass ratio of the thermally conductive particles in the positive electrode active material layer.

17. An electrical device comprising a battery according to any one of claims 9 to 16.

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