Secondary battery and electric device

Abstract

This application provides a secondary battery and an electrical device. The secondary battery includes an electrode assembly, an electrolyte, and a housing. The electrode assembly and electrolyte are housed in the housing. The housing includes a housing body and a functional coating on at least a portion of the wall surface of the housing body facing the electrode assembly. The functional coating includes a phase change material and a redox shuttle, with the redox shuttle located within the phase change material. This application provides a functional coating containing a redox shuttle and a phase change material on the inner wall of the housing, and by placing the redox shuttle within the phase change material, effectively isolates the redox shuttle from the electrolyte, thereby reducing the self-discharge problem caused by the redox shuttle directly dissolving in the electrolyte, which is beneficial for improving the stability of the secondary battery.

Description

Technical Field

[0001] This application relates to the field of lithium-ion secondary battery technology, specifically to a secondary battery and electrical equipment. Background Technology

[0002] Rechargeable batteries, as a new generation of energy storage and conversion devices, are widely used in portable electronic devices, electric vehicles, and other fields. After multiple cycles, dead lithium forms on the surface of the negative electrode in rechargeable batteries. Adding redox shuttles to the electrolyte can reactivate these dead lithium, but it may also introduce self-discharge problems, leading to poor battery stability. Therefore, improving the stability of rechargeable batteries is a pressing technical problem that needs to be solved. Utility Model Content

[0003] In view of this, the main technical problem to be solved in this application is how to improve the stability of secondary batteries.

[0004] To solve the above-mentioned technical problems, in a first aspect of this application, a secondary battery is provided. The secondary battery includes an electrode assembly, an electrolyte, and a housing. The electrode assembly and the electrolyte are housed in the housing. The housing includes a housing body and a functional coating located on at least a portion of the wall surface of the housing body facing the electrode assembly. The functional coating includes a phase change material and a redox shuttle, with the redox shuttle located within the phase change material.

[0005] In the technical solution of this application embodiment, a functional coating is provided on at least a portion of the wall surface of the housing body facing the electrode assembly. The functional coating includes a phase change material and a redox shuttle, and the redox shuttle is located within the phase change material. This enables the functional coating to undergo a phase change with changes in external temperature, thereby facilitating the release of the redox shuttle by adjusting the external temperature. Furthermore, the redox shuttle can react with dead lithium, oxidizing it into active lithium ions. This can increase the capacity of the secondary battery and reduce the probability of dead lithium puncturing the separator, thus improving the stability of the secondary battery.

[0006] Furthermore, during the activation of dead lithium in a secondary battery, the phase change material can undergo a phase change simply by adjusting the temperature of the casing, without having to bring the entire secondary battery to a preset temperature, which helps to save energy.

[0007] Furthermore, by placing the redox shuttle within the phase change material, the contact between the redox shuttle and the electrolyte can be effectively isolated, thereby reducing the self-discharge phenomenon and deactivation problem caused by the redox shuttle directly dissolving in the electrolyte, which is beneficial to increasing the utilization efficiency of the redox shuttle.

[0008] In some embodiments, the housing further includes a cover, the housing body having a bottom wall disposed opposite to the cover and a side wall connected to the bottom wall and extending toward the cover, the functional coating being located in at least a portion of the side wall.

[0009] In the embodiments of this application, by configuring the functional coating as described above, it is beneficial to fully utilize the surface inside the casing to coat a larger area of ​​functional coating, thereby achieving the activation effect on more dead lithium. Furthermore, it also helps to expand the heat exchange surface between the functional coating and the casing, thereby enabling faster heat transfer, improving heat transfer efficiency, and facilitating the rapid release of the redox shuttle.

[0010] In some embodiments, the housing further includes a cover, the housing body having a bottom wall disposed opposite to the cover and a side wall connected to the bottom wall and extending toward the cover, the functional coating being located in at least a portion of the bottom wall.

[0011] In the embodiments of this application, by setting the functional coating as described above, since there is more free electrolyte at the bottom of the shell, it is beneficial to uniformly disperse the redox shuttle released into the electrolyte. Furthermore, during the charging and discharging process, due to the periodic volume change of the electrode assembly, the redox shuttle located on the inner bottom wall is more likely to diffuse into the gaps inside the electrode assembly, thereby improving the activation efficiency of the redox shuttle.

[0012] In some embodiments, the secondary battery includes a first posture, which is the posture in which the secondary battery is configured as an electrical device placed on a horizontal surface, wherein the functional coating is immersed in an electrolyte.

[0013] In the embodiments of this application, by setting the functional coating to be immersed in the electrolyte, it is beneficial to directly release the redox shuttle into the electrolyte without changing the orientation of the secondary battery, which helps to simplify the dead lithium activation process.

[0014] In some embodiments, the secondary battery further includes a heating element located on at least a portion of the wall surface of the housing body on the side opposite to the electrode assembly.

[0015] In the embodiments of this application, by providing a heating element, the temperature of the shell body can be adjusted, so that the phase change material reaches the phase change temperature and undergoes a phase change, thereby releasing the redox shuttle.

[0016] In some embodiments, the heating element and the functional coating are located on opposite sides of the same wall of the housing body.

[0017] In the embodiments of this application, by setting the heating part and the functional coating on opposite sides of the same wall, it is beneficial to improve the heat transfer efficiency of the heating part to the functional coating, thereby facilitating the rapid release of the redox shuttle and saving energy.

[0018] In some embodiments, the secondary battery further includes a liquid cooling assembly having a heating section and a conductive section, wherein heat is conducted between the heating section and the conductive section through a liquid in the liquid flow path of the liquid cooling assembly, and the conductive section is located on at least a portion of the wall surface of the housing body on the side opposite to the electrode assembly.

[0019] In the embodiments of this application, by setting up a liquid cooling component, not only can the secondary battery be cooled and its temperature reduced during charging and discharging, but the secondary battery can also be heated during the activation of dead lithium, so that the phase change material reaches the phase change temperature and undergoes a phase change, thereby releasing the redox shuttle.

[0020] In some embodiments, the conductive portion and the functional coating are located on opposite sides of the same wall of the housing body.

[0021] In the embodiments of this application, by setting the conductive part and the functional coating on opposite sides of the same wall, it is beneficial to improve the heat transfer efficiency of the conductive part to the functional coating, thereby facilitating the rapid release of the redox shuttle and saving energy.

[0022] In some embodiments, the heating element has a preset heating temperature, which is greater than the phase change temperature of the phase change material.

[0023] In the embodiments of this application, the preset heating temperature is higher than the phase change temperature of the phase change material in order to cause the phase change material to undergo a phase change, thereby releasing the redox shuttle.

[0024] In some embodiments, the difference between the preset heating temperature and the phase change temperature of the phase change material is 1°C to 3°C.

[0025] In the embodiments of this application, setting the preset heating temperature to the above-mentioned range is beneficial to reducing the damage of high temperature to the secondary battery and to releasing the redox shuttle.

[0026] In some embodiments, the phase transition temperature T of the phase change material m For: 60℃≤T m ≤80℃.

[0027] In the embodiments of this application, the phase transition temperature T of the phase change material is controlled. m Within a certain range, on the one hand, it is beneficial to save energy consumption, as the phase change material can undergo a phase change at a relatively low temperature, thereby releasing the redox shuttle. On the other hand, it is also beneficial to reduce the damage to the battery interior caused by high temperature, thereby improving the stability of the secondary battery.

[0028] In some embodiments, the phase change material is a paraffinic hydrocarbon, a saturated fatty acid, or a polyester polymer.

[0029] In the embodiments of this application, by setting the phase change material to include the above-mentioned materials, since paraffin hydrocarbons, saturated fatty acids or polyester polymers usually have good chemical stability, the impact of the phase change material on the performance of the secondary battery can be reduced.

[0030] In some embodiments, the redox shuttle is one of ferrocene, piperidine oxygen radical compounds, pyridine oxygen radical compounds, quinone compounds, phenanthroline iron complexes, bipyridine iron complexes, and their derivatives.

[0031] In the embodiments of this application, by setting the redox shuttle to include the above-mentioned materials, the redox shuttle has the ability to activate dead lithium, that is, the redox shuttle can react with dead lithium, causing the dead lithium to be oxidized into active lithium ions, thereby reducing the probability of dead lithium puncturing the separator, which is beneficial to improving the stability of the secondary battery.

[0032] In some embodiments, the secondary battery includes a voltage regulation component, the output of which is electrically connected to the input of the electrode assembly, and the output voltage of the voltage regulation component is greater than the oxidation peak potential of the redox shuttle.

[0033] In the embodiments of this application, by setting a voltage regulation component, the voltage of the secondary battery can be regulated, and the output voltage of the voltage regulation component is greater than the oxidation peak potential of the redox shuttle, which can activate the redox shuttle, thereby enabling the redox shuttle to achieve the effect of dead lithium activation.

[0034] In some embodiments, the voltage regulation component includes a power supply module and a control module. The power supply module is connected between the secondary battery and the external circuit, and the control module is connected between the power supply module and the secondary battery. The control module is used to respond to a voltage regulation control signal and control the output voltage of the power supply module to the secondary battery.

[0035] In the embodiments of this application, by setting the voltage regulation component to include the above-mentioned modules, the voltage regulation component can accurately control the output voltage of the power module to the secondary battery according to the requirements, ensuring that the secondary battery can obtain a stable and appropriate voltage under charging, discharging and other operating conditions.

[0036] In some embodiments, the control module is also connected between the heating element and the power module, and the control module is also used to control the preset heating temperature of the heating element.

[0037] In the embodiments of this application, by setting a control module connected between the heating part and the power module, the preset heating temperature of the heating part can be adjusted by the voltage regulation component, which helps to reduce the complexity of the circuit.

[0038] In some embodiments, the thickness of the functional coating is 1 μm to 10 μm.

[0039] In the embodiments of this application, by controlling the thickness of the functional coating within a suitable range, it is beneficial to increase the amount of functional coating applied to the shell body, thereby improving the dead lithium activation effect of the functional coating and also improving heat transfer efficiency, thus achieving the goal of saving energy.

[0040] A second aspect of this application provides an electrical device that includes any of the secondary batteries provided in the first aspect. The electrical device provided by the embodiments of this application, by including any of the secondary batteries provided in the first aspect, has at least the same advantages as a secondary battery. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a cross-sectional schematic diagram of the first embodiment of the secondary battery provided in this application;

[0043] Figure 2 This is a cross-sectional schematic diagram of the second embodiment of the secondary battery provided in this application;

[0044] Figure 3 This is a cross-sectional schematic diagram of the third embodiment of the secondary battery provided in this application;

[0045] Figure 4 This is a cross-sectional schematic diagram of the electrode assembly of the secondary battery provided in the embodiments of this application;

[0046] Figure 5 This is a schematic diagram of the structure of the first embodiment of the functional particles of the secondary battery provided in this application.

[0047] Figure 6 This is a schematic diagram of the structure of the functional particles of the secondary battery provided in the embodiments of this application;

[0048] Figure 7 This is a schematic diagram of the third embodiment of the functional particles of the secondary battery provided in this application.

[0049] Figure 8 This is a schematic diagram of the structure of the fourth embodiment of the functional particles of the secondary battery provided in this application;

[0050] Figure 9 This is a scanning electron microscope image of the first embodiment of the functional particles of the secondary battery provided in this application.

[0051] Figure 10 This is a scanning electron microscope image of a cross section of the functional particles of the secondary battery provided in the embodiments of this application.

[0052] Figure 11 This is a scanning electron microscope image of a second embodiment of the functional particles of the secondary battery provided in this application.

[0053] Figure 12 This is a scanning electron microscope image of the fourth embodiment of the functional particles of the secondary battery provided in this application.

[0054] Figure 13 This is a schematic diagram of the structure of the secondary battery provided in the embodiments of this application;

[0055] Figure 14 This is an exploded structural diagram of the secondary battery provided in an embodiment of this application;

[0056] Figure 15 This is an exploded view of the battery pack provided in an embodiment of this application;

[0057] Figure 16 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application.

[0058] Explanation of icon numbers:

[0059] 1000-Electrical equipment, 100-Battery pack, 200-Controller, 300-Motor, 10-Box, 11-First part, 12-Second part, 20-Secondary battery, 21-Cover, 21a-Electrode terminal, 22-Shell, 22a-Shell body, 22b-Functional coating, 22c-Side wall, 22d-Bottom wall, 23-Electrode assembly, 23a-Taper, 23b-Positive electrode, 23c-Negative electrode, 23d-Separator, 24-Electrolyte, 25-Heating part, 26-Phase change material, 27-Redox shuttle, 28-Functional particles, 29-Shell, Pores 29a, 30-Liquid cooling assembly, 30a-Conductive part, 31-Voltage regulation assembly, 31a-Power module, 31b-Control module. Detailed Implementation

[0060] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, and not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0061] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0062] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0063] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0064] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0065] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0066] After multiple cycles, the process of lithium ions intercalating into the negative electrode active material becomes increasingly difficult due to the degradation of kinetic performance in secondary batteries. Metallic lithium gradually precipitates on the negative electrode surface, and this precipitated lithium is generally unrecyclable, hence the term "dead lithium." The formation of these dead lithium leads to a decrease in battery capacity and makes the separator prone to puncture, causing short circuits and severely degrading battery stability. Currently, engineers in this field typically add redox shuttles to the electrolyte to reactivate dead lithium; however, the introduction of redox shuttles may also introduce self-discharge problems, resulting in poor stability of the secondary battery.

[0067] To solve the above problems, refer to Figures 1-3 In a first aspect, a secondary battery 20 is provided. The secondary battery 20 includes an electrode assembly 23, an electrolyte 24, and a housing 22. The electrode assembly 23 and the electrolyte 24 are housed in the housing 22. The housing 22 includes a housing body 22a and a functional coating 22b located on at least a portion of the wall surface of the housing body 22a facing the electrode assembly 23. The functional coating 22b includes a phase change material 26 and a redox shuttle 27, with the redox shuttle 27 located within the phase change material 26.

[0068] The casing 22 isolates the internal environment of the secondary battery 20 from the external environment. Furthermore, the casing 22 possesses a certain degree of hardness and strength, making it less prone to deformation under pressure and impact, thus improving the stability of the secondary battery 20. The casing 22 can be of any shape, including but not limited to square, cylindrical, and prismatic shapes. The casing 22 can be a hollow structure to accommodate objects such as the electrode assembly 23 and the electrolyte 24. The casing 22 includes walls, which can be any side of the casing 22. For example, when the casing 22 is square, the six inner sides facing the internal electrolyte 24 and the six outer sides facing away from the internal electrolyte 24 can all serve as walls of the casing 22.

[0069] Phase change material 26 is a material capable of changing its physical state within a certain temperature range. The physical state of the material includes solid, liquid, and gas phases. For example, taking a solid-liquid phase change system as an example, when heated to the melting temperature, phase change material 26 undergoes a phase change from solid to liquid. During the phase change process, phase change material 26 absorbs and stores a large amount of heat.

[0070] Redox shuttle 27 is an additive used in secondary battery 20 to improve the stability and performance of secondary battery 20. Specifically, during charging, redox shuttle 27 is first oxidized into cations on the positive electrode surface, and then diffuses to the negative electrode region through electrolyte 24. These cations can act as electron acceptors, oxidizing the deposited dead lithium, eliminating the dead lithium and reactivating it into active lithium ions. At the same time, these cations are reduced and reset into redox shuttle 27, which diffuses to the positive electrode surface through electrolyte 24 to begin the next round of redox cycle.

[0071] In the technical solution of this application embodiment, a functional coating 22b is provided on at least a portion of the wall surface of the housing body 22a facing the electrode assembly 23, facilitating the subsequent release of the redox shuttle in the functional coating 22b into the electrolyte 24. Furthermore, by providing the functional coating 22b with a phase change material 26 and a redox shuttle 27, and by positioning the redox shuttle 27 within the phase change material 26, the functional coating 22b possesses the ability to undergo a phase change with changes in external temperature, thereby facilitating the release of the redox shuttle 27 by adjusting the external temperature. Further, the redox shuttle 27 can react with dead lithium, oxidizing it into active lithium ions, thereby reducing the probability of dead lithium puncturing the separator 23d, which is beneficial for improving the stability of the secondary battery 20. In addition, the phase change material 26 can undergo a phase change simply by adjusting the temperature of the housing 22, without needing to bring the entire secondary battery 20 to a preset temperature, which is beneficial for saving energy. Furthermore, by placing the redox shuttle 27 within the phase change material 26, the redox shuttle 27 can be effectively isolated from contact with the electrolyte 24, thereby reducing the self-discharge phenomenon and deactivation problem caused by the redox shuttle 27 directly dissolving in the electrolyte 24, which is beneficial to increasing the utilization efficiency of the redox shuttle 27.

[0072] In some embodiments, please refer to Figure 1 The housing 22 also includes a cover 21, and the housing body 22a has a bottom wall 22d disposed opposite to the cover 21 and a side wall 22c connected to the bottom wall 22d and extending toward the cover 21, and the functional coating 22b is located in at least a portion of the side wall 22c.

[0073] For example, when the housing 22 is square, the housing body 22a is a square shape with an opening, the cover 21 is used to close the opening, and the housing body 22a has a bottom wall 22d disposed opposite to the cover 21 and four side walls 22c connected to the bottom wall 22d and extending toward the cover 21.

[0074] In the embodiments of this application, by configuring the functional coating 22b as described above, it is beneficial to fully utilize the surface inside the housing body 22a to coat a larger area of ​​the functional coating 22b, thereby achieving the activation effect on more dead lithium. In addition, it is also beneficial to expand the heat exchange surface between the functional coating and the housing, thereby enabling faster heat transfer, improving heat transfer efficiency, and facilitating the rapid release of the redox shuttle 27.

[0075] In some embodiments, please refer to Figure 2 The housing 22 also includes a cover 21. The housing body 22a has a bottom wall 22d disposed opposite to the cover 21 and a side wall 22c connected to the bottom wall 22d and extending toward the cover 21. The functional coating 22b is located in at least a portion of the bottom wall 22d.

[0076] In the embodiments of this application, by setting the functional coating 22b as described above, since there is more free electrolyte 24 at the bottom of the housing 22, it is beneficial to uniformly disperse the redox shuttle 27 released into the electrolyte 24. Furthermore, during the charging and discharging process, due to the periodic volume change of the electrode assembly 23, the redox shuttle 27 located on the bottom wall 22d is more likely to diffuse into the gaps inside the electrode assembly 23, thereby improving the activation efficiency of the redox shuttle 27.

[0077] In some embodiments, the secondary battery 20 includes a first posture, which is the posture in which the secondary battery 20 is configured as an electrical device placed on a horizontal surface, wherein the functional coating 22b is immersed in the electrolyte 24.

[0078] The first posture of the secondary battery 20 refers to the posture in which the secondary battery 20 is positioned within the electrical device under normal operating conditions. For example, taking an electric vehicle as an example, the first posture of the secondary battery 20 within the electric vehicle is the posture in which the secondary battery 20 is positioned when the electric vehicle is parked or driving on a level surface. Optionally, the secondary battery 20 may also include a second posture and a third posture. The second posture is the posture of the secondary battery 20 when it is configured to be placed on an inclined surface, and the third posture is the posture of the secondary battery 20 when it is configured to be placed on a vertical surface. Optionally, in other embodiments, the secondary battery 20 may also include postures other than the first, second, and third postures, such as an inverted posture opposite to the first posture.

[0079] In the embodiments of this application, by setting the functional coating 22b to be immersed in the electrolyte 24 in the first posture, it is beneficial to directly release the redox shuttle 27 into the electrolyte 24 without changing the posture of the secondary battery 20, which helps to simplify the dead lithium activation step.

[0080] In some embodiments, refer to Figures 5-8 As shown, the functional coating 22b includes functional particles 28, which include a phase change material 26 and a redox shuttle 27.

[0081] In the embodiments of this application, by setting the functional coating 22b to include functional particles 28 in a granular shape, it is beneficial to increase the specific surface area of ​​the functional coating 22b, so that the redox shuttle 27 released later can quickly diffuse into the electrolyte 24, thereby improving the efficiency of dead lithium activation.

[0082] In some embodiments, such as Figure 5As shown, the functional particle 28 includes a capsule structure, which includes a capsule core and a capsule wall covering the capsule core. The capsule wall includes a phase change material 26, and the capsule core includes a redox shuttle 27.

[0083] In the embodiments of this application, by setting the functional particles 28 into a capsule structure, the contact between the redox shuttle 27 and the electrolyte 24 can be effectively reduced, thereby reducing the self-discharge phenomenon and self-deactivation problem caused by the direct dissolution of the redox shuttle 27 in the electrolyte 24, and improving the utilization efficiency of the redox shuttle 27. Scanning electron microscopy (SEM) is used to obtain the material morphology and microstructure information. Specifically, the functional particles 28 of this embodiment are analyzed by scanning electron microscopy, and the morphology characterization results are as follows: Figure 9 and Figure 10 As shown, from Figure 10 As can be seen from the figure, the functional particles 28 prepared in this embodiment have a typical capsule structure. The whitish capsule wall is the phase change material 26, and the dark-colored capsule core is the redox shuttle 27. The redox shuttle 27 is encapsulated within the phase change material 26.

[0084] In some embodiments, such as Figure 6 As shown, the functional particles 28 include a phase change material 26 and a redox shuttle 27 discretely distributed within the phase change material 26.

[0085] In the embodiments of this application, by setting the functional particles 28 to the above-described structure, the contact between the redox shuttle 27 and the electrolyte 24 can be effectively reduced, thereby reducing the self-discharge phenomenon and self-deactivation problem caused by the direct dissolution of the redox shuttle 27 in the electrolyte 24, and improving the utilization efficiency of the redox shuttle 27. Scanning electron microscopy (SEM) is used to obtain the material morphology and microstructure information. Specifically, the functional particles 28 of this embodiment are analyzed by scanning electron microscopy, and the morphology characterization results are as follows: Figure 11 As shown in the figure, the functional particles 28 prepared in this embodiment are formed by the copolymerization of multiple phase change materials 26, and the redox shuttle 27 is discretely distributed in the aggregates formed by the copolymerization of multiple phase change materials 26.

[0086] In some embodiments, such as Figures 7-8 As shown, the functional particle 28 includes a shell 29 and an inner core. The shell 29 has a porous structure, and the inner core includes a phase change material 26 and a redox shuttle 27. The shell 29 has pores 29a. The phase change material 26 and the redox shuttle 27 are located in the pores 29a of the shell 29, and the redox shuttle 27 is discretely distributed in the phase change material 26.

[0087] In the embodiments of this application, by setting the functional particles 28 to the above-described structure, the contact between the redox shuttle 27 and the electrolyte 24 can be further effectively reduced, thereby reducing the self-discharge phenomenon and self-deactivation problem caused by the direct dissolution of the redox shuttle 27 in the electrolyte 24, and improving the utilization efficiency of the redox shuttle 27. Furthermore, the outer shell 29 can increase the mechanical strength and structural stability of the functional particles 28, thereby reducing the probability of leakage of the redox shuttle 27. Also, after the phase change material 26 undergoes a phase change, the supporting effect of the outer shell 29 can alleviate the collapse or detachment of the functional coating 22b, thereby reducing the impact of the phase change material 26 on the performance of the secondary battery 20. Scanning electron microscopy (SEM) is used to obtain the material morphology and microstructure information. Specifically, the functional particles 28 of this embodiment are analyzed by scanning electron microscopy, and the morphology characterization results are as follows: Figure 12 As shown, the outer shell 29 used in this embodiment is an inorganic silicon shell with a structure similar to a hollow cage structure.

[0088] In some embodiments, the particle size Dv50 of the shell 29 is 0.5 μm to 3.0 μm, and / or the pore size of the shell 29 is 0.05 μm to 0.30 μm.

[0089] The particle size Dv50 of the outer shell 29 can be 0.5μm, 0.7μm, 1.0μm, 1.4μm, 2.0μm, 2.5μm, 3.0μm, etc., or it can be a range of any two of the above values, such as 0.5μm~2.0μm, 1.4μm~2.5μm, 0.7μm~2.5μm, 2.0μm~3.0μm, etc.

[0090] The aperture of the outer shell 29 can be 0.05μm, 0.07μm, 0.10μm, 0.14μm, 0.20μm, 0.25μm, 0.30μm, etc., or it can be a range of any two of the above values, such as 0.05μm~0.20μm, 0.14μm~0.25μm, 0.07μm~0.25μm, 0.20μm~0.30μm, etc.

[0091] In the embodiments of this application, by setting the particle size Dv50 and pore size of the shell 29 within the above-mentioned range, on the one hand, during the preparation process, it is beneficial for the phase change material 26 and the redox shuttle 27 to enter the pores 29a of the shell 29; on the other hand, during use, it is beneficial to improve the release of the redox shuttle 27 from the pores 29a of the shell 29, enhance the dead lithium activation ability of the functional particles 28, and improve the utilization efficiency of the redox shuttle 27.

[0092] In some embodiments, the functional coating 22b further includes an adhesive.

[0093] In the embodiments of this application, the adhesive can improve the adhesion between the functional coating 22b and the housing body 22a, which is beneficial to the fixation of the functional coating 22b on the housing body 22a.

[0094] In some embodiments, please refer to Figure 1 and Figure 2 The secondary battery 20 also includes a heating element 25, which is located on at least a portion of the wall surface of the housing body 22a on the side opposite to the electrode assembly 23.

[0095] In the embodiments of this application, by providing a heating part 25, the temperature of the shell body 22a can be adjusted, so that the phase change material 26 reaches the phase change temperature and undergoes a phase change, thereby releasing the redox shuttle 27.

[0096] Optionally, the heating part 25 includes at least one of silicone heating band, PET heating film, glass fiber heating band, polyimide heating sheet and heating wire.

[0097] In some embodiments, please refer to Figure 1 and Figure 2 The heating element 25 and the functional coating 22b are located on opposite sides of the same wall of the housing body 22a.

[0098] In the embodiments of this application, by setting the heating part 25 and the functional coating 22b on opposite sides of the same wall, it is beneficial to improve the heat transfer efficiency of the heating part 25 to the functional coating 22b, thereby facilitating the rapid release of the redox shuttle 27 and saving energy.

[0099] In some embodiments, such as Figure 3 As shown, the secondary battery 20 also includes a liquid cooling assembly 30, which has a heating part 25 and a conductive part 30a. The heating part 25 and the conductive part 30a are heat-conducted between each other through the liquid in the liquid flow path of the liquid cooling assembly 30. The conductive part 30a is located on at least a portion of the wall surface of the housing body 22a on the side opposite to the electrode assembly 23.

[0100] In the embodiments of this application, by setting the liquid cooling component 30, not only can the secondary battery 20 be cooled and its temperature reduced during charging and discharging, but the secondary battery 20 can also be heated, so that the phase change material 26 reaches the phase change temperature and undergoes a phase change, thereby releasing the redox shuttle 27.

[0101] In some embodiments, such as Figure 3 As shown, the conductive part 30a and the functional coating 22b are located on opposite sides of the same wall of the housing body 22a.

[0102] In the embodiments of this application, by setting the conductive part 30a and the functional coating 22b on opposite sides of the same wall, it is beneficial to improve the heat transfer efficiency of the conductive part 30a to the functional coating 22b, thereby facilitating the rapid release of the redox shuttle 27 and saving energy.

[0103] In some embodiments, the heating part 25 has a preset heating temperature, which is greater than the phase change temperature of the phase change material 26.

[0104] In the embodiments of this application, the preset heating temperature is higher than the phase change temperature of the phase change material 26 in order to cause the phase change material 26 to undergo a phase change, thereby releasing the redox shuttle 27.

[0105] In some embodiments, the difference between the preset heating temperature and the phase change temperature of the phase change material 26 is 1°C to 3°C.

[0106] The difference between the preset heating temperature and the phase change temperature of the phase change material 26 can be 1℃, 1.2℃, 1.8℃, 2.5℃, 2.9℃, 3℃, etc., or it can be a range of any two of the above values, such as 1℃~1.2℃, 1.2℃~2.9℃, 2.9℃~3℃, etc.

[0107] In the embodiments of this application, setting the preset heating temperature within the aforementioned range is beneficial for reducing damage to the secondary battery 20 and for releasing the redox shuttle 27. On the one hand, if the preset heating is too high, it will damage the internal structure of the secondary battery 20 and cause unnecessary heat waste. On the other hand, if the preset temperature is too low, the phase change material 26 cannot undergo a phase change, that is, the redox shuttle 27 cannot be released.

[0108] In some embodiments, the phase transition temperature T of the phase change material 26 m For: 60℃≤T m ≤80℃.

[0109] Phase transition temperature T m It refers to the temperature at which a substance transitions between different phases. It is common knowledge in the field and has a common meaning in the field. It can be measured by methods and instruments in the field.

[0110] In any embodiment, the phase transition temperature T of the phase change material 26 is... m It can be 60℃, 65℃, 70℃, 74℃, 78℃, 80℃, etc., or a range consisting of any two of the above values, such as 60℃~65℃, 65℃~78℃, 78℃~80℃, etc.

[0111] In the embodiments of this application, the phase change temperature T of the phase change material 26 is controlled. mWithin a certain range, on the one hand, it is beneficial to save energy consumption, as the phase change material 26 can undergo a phase change at a relatively low temperature, thereby releasing the redox shuttle 27. On the other hand, it is also beneficial to reduce the damage of high temperature to the interior of the secondary battery 20, thereby improving the stability of the secondary battery 20.

[0112] In some embodiments, the phase change material 26 is a paraffinic hydrocarbon, a saturated fatty acid, or a polyester polymer.

[0113] In the embodiments of this application, by providing the phase change material 26 to include the above-mentioned materials, since paraffin hydrocarbons, saturated fatty acids or polyester polymers usually have good chemical stability, the impact of the phase change material 26 on the performance of the secondary battery 20 can be reduced.

[0114] In some embodiments, the phase change material 26 may include a variety of phase change materials 26 with different phase change temperatures. The phase change materials 26 with different phase change temperatures are disposed in different regions of the inner wall. According to different heating temperatures, the redox shuttle 27 in different regions is released, thereby enabling multiple dead lithium activation treatments of the secondary battery 20.

[0115] In some embodiments, the oxidation peak potential of the redox shuttle 27 is greater than or equal to the oxidation peak potential of the positive electrode active material and less than the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage; and / or the oxidation peak potential of the redox shuttle 27 is greater than or equal to the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage.

[0116] The potential described in this application is relative to (Li + The potential obtained from the / Li electrode potential is common knowledge in the field, has a common meaning in the field, and can be measured by methods and instruments in the field.

[0117] The redox shuttle 27 of the functional coating 22b may include multiple redox shuttles 27 with different oxidation peak potentials. Optionally, the redox shuttle 27 of the functional coating 22b includes a first redox shuttle and a second redox shuttle, wherein the oxidation peak potential of the first redox shuttle is greater than or equal to the oxidation peak potential of the positive electrode active material and less than the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage, and the oxidation peak potential of the second redox shuttle is greater than or equal to the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage. In this case, when the first lithium dead activation is required, cycling within the normal charge and discharge voltage range can be performed to activate the first redox shuttle. When the second lithium dead activation is required in the later stage, the charging cutoff voltage can be increased to enable the second redox shuttle to be activated and oxidized.

[0118] In some embodiments, the redox shuttle 27 is one of ferrocene, piperidine oxygen radical compounds, pyridine oxygen radical compounds, quinone compounds, phenanthrene-iron complexes, bipyridine iron complexes, and their derivatives.

[0119] In the embodiments of this application, by setting the redox shuttle 27 to include the above-mentioned materials, the redox shuttle 27 has the ability to activate dead lithium, that is, the redox shuttle 27 can react with dead lithium, causing the dead lithium to be oxidized into active lithium ions, thereby reducing the probability of dead lithium puncturing the separator 23d, which is beneficial to improving the stability of the secondary battery 20.

[0120] In some embodiments, such as Figure 13 As shown, the secondary battery 20 includes a voltage regulation component 31. The output terminal of the voltage regulation component 31 is electrically connected to the input terminal of the electrode component 23. The output voltage of the voltage regulation component 31 is greater than the oxidation peak potential of the redox shuttle 27.

[0121] In the embodiments of this application, by setting the voltage regulation component 31, the voltage of the secondary battery 20 can be regulated, and the output voltage of the voltage regulation component 31 is greater than the oxidation peak potential of the redox shuttle 27, which can activate the redox shuttle 27, thereby enabling the redox shuttle 27 to achieve the effect of dead lithium activation.

[0122] In some embodiments, the voltage regulation component 31 includes a power supply module 31a and a control module 31b. The power supply module 31a is connected between the secondary battery 20 and the external circuit, and the control module 31b is connected between the power supply module 31a and the secondary battery 20. The control module 31b is used to control the output voltage of the power supply module 31a to the secondary battery 20 in response to a voltage regulation control signal.

[0123] In the embodiments of this application, by setting the voltage regulation component 31 to include the above-mentioned modules, the voltage regulation component 31 can accurately control the output voltage of the power module 31a to the secondary battery 20 as needed, ensuring that the secondary battery 20 can obtain a stable and appropriate voltage under charging, discharging and other operating conditions.

[0124] In some embodiments, the control module 31b is also connected between the heating unit 25 and the power module 31a, and the control module 31b is also used to control the preset heating temperature of the heating unit 25.

[0125] In the embodiments of this application, by setting the control module 31b to be connected between the heating part 25 and the power module 31a, the preset heating temperature of the heating part 25 can be adjusted by the voltage adjustment component 31, which helps to reduce the complexity of the circuit.

[0126] In some embodiments, when the oxidation peak potential of the redox shuttle 27 is greater than or equal to the oxidation peak potential of the positive electrode active material and less than the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage, the output voltage of the voltage regulating component 31 includes a first voltage, and the difference between the first voltage and the oxidation peak potential of the redox shuttle 27 is in the range of 0.5V to 1V.

[0127] The difference between the first voltage and the oxidation peak potential of the redox shuttle 27 can be 0.5V, 0.6V, 0.7V, 0.8V, 0.9V, 1V, etc., or it can be a range of any two of the above values, such as 0.5V~0.6V, 0.6V~0.9V, 0.9V~1V, etc.

[0128] In the embodiments of this application, by setting the range of the first voltage as described above, the deactivation effect of the redox shuttle 27 can be achieved, thereby eliminating the redox shuttle 27. In addition, the damage of overcharging to the secondary battery 20 can be reduced.

[0129] In some embodiments, when the oxidation peak potential of the redox shuttle 27 is greater than or equal to the potential of the positive electrode active material when the secondary battery 20 reaches the charging cutoff voltage, the output voltage of the voltage regulation component includes a second voltage, and the difference between the second voltage and the oxidation peak potential of the redox shuttle 27 is in the range of 0V to 0.5V.

[0130] The difference between the second voltage and the oxidation peak potential of the redox shuttle 27 can be 0V, 0.1V, 0.2V, 0.3V, 0.4V, 0.5V, etc., or it can be a range composed of any two of the above values, such as 0V~0.1V, 0.1V~0.4V, 0.4V~0.5V, etc.

[0131] In the embodiments of this application, by setting the range of the second voltage as described above, the activation of the redox shuttle 27 and the saving of energy consumption can be achieved. In addition, the damage of overcharging to the secondary battery 20 can be reduced.

[0132] In some embodiments, the output voltage of the voltage regulation component further includes a third voltage, which is greater than the second voltage, and the difference between the third voltage and the oxidation peak potential of the redox shuttle 27 is in the range of 0.5V to 1V.

[0133] The difference between the third voltage and the oxidation peak potential of the redox shuttle 27 can be 0.5V, 0.6V, 0.7V, 0.8V, 0.9V, 1V, etc., or it can be a range of any two of the above values, such as 0.5V~0.6V, 0.6V~0.9V, 0.9V~1V, etc.

[0134] In the embodiments of this application, by setting the range of the third voltage as described above, the deactivation effect of the redox shuttle 27 can be achieved, thereby eliminating the redox shuttle 27. In addition, the damage of overcharging to the secondary battery 20 can be reduced.

[0135] In some embodiments, the thickness of the functional coating 22b is 1 μm to 10 μm.

[0136] The thickness of the functional coating 22b can be 1μm, 2μm, 3μm, 6μm, 9μm, 10μm, etc., or it can be a range of any two of the above values, such as 1μm~3μm, 3μm~6μm, 6μm~10μm, etc.

[0137] In the embodiments of this application, by controlling the thickness of the functional coating 22b within a suitable range, it is beneficial to increase the amount of the functional coating 22b coated on the housing body 22a, thereby improving the dead lithium activation effect of the functional coating 22b and also improving the heat transfer efficiency, thus achieving the goal of saving energy.

[0138] In one embodiment, the method for preparing the functional coating 22b includes: mixing functional particles 28, a binder, and a solvent to form a coating slurry, wherein the functional particles 28 have a capsule structure, the functional particles 28 include a capsule core and a capsule wall covering the capsule core, the capsule wall includes a phase change material 26, and the capsule core includes a redox shuttle 27; applying the coating slurry to at least a portion of the electrode assembly 23, and then curing it to obtain the functional coating 22b.

[0139] Furthermore, the preparation method of functional particles 28 includes: thoroughly mixing a first polymerizing monomer, a second polymerizing monomer, a redox shuttle 27, a catalyst, and a nonpolar solvent to form an oil phase; adding a surfactant to deionized water and stirring thoroughly to obtain an emulsion; heating the emulsion to 50℃~80℃, then adding the oil phase to the emulsion and reacting for 1h~24h to obtain an intermediate product; washing the intermediate product with water and vacuum drying it at 45℃~60℃ for 1h~24h to obtain functional particles 28 with a capsule structure.

[0140] Furthermore, the phase change material 26 includes a polyester polymer, wherein the polymer monomers of the polyester polymer include at least one of C5-C10 dicarboxylic acids and at least one of C2-C10 diols.

[0141] Furthermore, the first polymerization monomer includes at least one of the C5 to C10 dicarboxylic acids; and / or the second polymerization monomer includes at least one of the C2 to C10 diols.

[0142] Furthermore, C5-C10 dicarboxylic acids include glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, cycloglutaric acid, etc.; C2-C10 diols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, 1,2-butanediol, etc.

[0143] Furthermore, the mass ratio of the first polymerizing monomer, the second polymerizing monomer, the redox shuttle 27, and the catalyst is (80-2000):(80-2000):(20-500):1.

[0144] For example, the mass ratio of the first polymerizing monomer, the second polymerizing monomer, the redox shuttle 27, and the catalyst can be 80:80:20:1, 80:80:300:1, 80:80:500:1, 80:1000:300:1, 80:2000:300:1, 1000:1000:300:1, 2000:2000:500:1, etc.

[0145] Further, the catalyst includes at least one of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate, dimethyltin oxide, dibutyltin oxide, dioctyltin oxide, and dibutyltin dilaurate; and / or the nonpolar solvent includes at least one of cyclohexane, dichloromethane, acetone, benzene, toluene, xylene, and N,N-dimethylformamide; and / or the surfactant includes at least one of Tween-20, Tween-60, Tween-80, Span-20, Span-40, Span-60, and Span-80.

[0146] Furthermore, the solid content of the coating slurry is 3wt% to 10wt%.

[0147] For example, the solid content of the coating slurry can be 3wt%, 5wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc., or a range of any two of the above values, such as 3wt% to 5wt%, 5wt% to 8wt%, 8wt% to 10wt%, etc.

[0148] In one embodiment, the method for preparing the functional coating 22b includes: mixing functional particles 28, a binder, and deionized water to form a coating slurry, wherein the functional particles 28 include a phase change material 26 and a redox shuttle 27, and the redox shuttle 27 is discretely distributed within the phase change material 26; applying the coating slurry to at least a portion of the electrode assembly 23, and then curing it to obtain the functional coating 22b.

[0149] Furthermore, the preparation method of functional particles 28 includes: mixing phase change material 26, redox shuttle 27 and a first solvent to form a precursor solution; spray drying the precursor solution to obtain an intermediate product; washing the intermediate product with a second solvent and drying it to obtain functional particles 28.

[0150] Furthermore, the phase change material 26 includes at least one of paraffinic hydrocarbons of C28 to C37 and saturated fatty acids of C18 to C22.

[0151] Furthermore, the mass ratio of phase change material 26 to redox shuttle 27 is (0.1–5):1.

[0152] The mass ratio of phase change material 26 to redox shuttle 27 can be 0.1:1, 1:1, 2:1, 3:1, 4:1, 5:1, or any range of any two of the above values, such as (0.1~2):1, (2~4):1, (4~5):1, etc.

[0153] Furthermore, the solid content of the precursor solution is 30wt% to 50wt%.

[0154] The solid content of the precursor solution can be 30wt%, 35wt%, 40wt%, 42wt%, 48wt%, 50wt%, etc., or a range of any two of the above values, such as 30wt%~40wt%, 40wt%~42wt%, 42wt%~50wt%, etc.

[0155] Furthermore, the inlet air temperature of the spray dryer is 60℃~80℃; and / or the outlet air temperature of the spray dryer is 50℃~60℃; and / or the atomization speed of the spray dryer is 15000rpm~25000rpm.

[0156] The inlet air temperature for spray drying can be 60℃, 65℃, 70℃, 75℃, 78℃, 80℃, or any range of two of the above values, such as 60℃~70℃, 70℃~75℃, 75℃~80℃, etc.; the outlet air temperature for spray drying can be 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, or any range of two of the above values, such as 50℃~54℃, 54℃~58℃, 58℃~60℃, etc.; the atomization speed for spray drying can be 15000rpm, 17000rpm, 19000rpm, 21000rpm, 23000rpm, 25000rpm, or any range of two of the above values, such as 15000rpm~19000rpm, 19000rpm~21000rpm, 21000rpm~25000rpm, etc.

[0157] Furthermore, the first solvent includes at least one of isobutanol, n-butanol, isopropanol, n-pentanol, and isoamyl alcohol; and / or the second solvent includes at least one of deionized water, ethanol, and n-propanol.

[0158] Furthermore, the solid content of the coating slurry is 3wt% to 10wt%.

[0159] The solid content of the coating slurry can be 3wt%, 4wt%, 6wt%, 8wt%, 9wt%, 10wt%, etc., or a range of any two of the above values, such as 3wt%~6wt%, 6wt%~8wt%, 8wt%~10wt%, etc.

[0160] In one embodiment, the method for preparing the functional coating 22b includes: mixing functional particles 28, a binder, and deionized water to form a coating slurry, wherein the functional particles 28 include a shell 29 and an inner core, the shell 29 having a porous structure, and the inner core including a phase change material 26 and a redox shuttle 27, the redox shuttle 27 being discretely distributed within the phase change material 26; applying the coating slurry to at least a portion of the electrode assembly 23, and then curing it to obtain the functional coating 22b.

[0161] Furthermore, the preparation method of functional particles 28 includes: mixing phase change material 26, redox shuttle 27 and solvent, and stirring at 60℃~100℃ to form a first mixture; adding shell 29 to the first mixture and stirring at 50℃~65℃ to form a second mixture; filtering the second mixture to obtain an intermediate product, washing the intermediate product with solvent, and drying it to obtain functional particles 28.

[0162] Furthermore, the outer shell 29 includes at least one of SiO2, AlO3, BaTiO3, TiO2, SiC, and ZnO.

[0163] Furthermore, the phase change material 26 includes at least one of paraffinic hydrocarbons of C28 to C37 and saturated fatty acids of C18 to C22.

[0164] Furthermore, the mass ratio of phase change material 26, redox shuttle 27, and shell 29 is (0.33~5):(0.1~2):1.

[0165] For example, the mass ratio of phase change material 26, redox shuttle 27, and shell 29 can be 0.33:0.1:1, 0.33:1:1, 0.33:2:1, 2:0.1:1, 2:1:1, 2:2:1, 5:0.1:1, 5:1:1, 5:2:1, etc.

[0166] Furthermore, the solvent includes at least one of isobutanol, n-butanol, isopropanol, n-pentanol, n-propanol, deionized water, and ethanol.

[0167] Furthermore, the solid content of the coating slurry is 4wt% to 8wt%.

[0168] For example, the solid content of the coating slurry can be 4wt%, 5wt%, 6wt%, 6.5wt%, 7wt%, 8wt%, etc., or a range of any two of the above values, such as 4wt% to 6wt%, 6wt% to 7wt%, 7wt% to 8wt%, etc.

[0169] A second aspect of this application provides an electrical device 1000 including any of the secondary batteries 20 provided in the first aspect. The electrical device 1000 provided in the embodiments of this application, by including any of the secondary batteries 20 provided in the first aspect, has at least the same advantages as the secondary batteries 20.

[0170] In addition, the secondary battery 20, battery pack 100 and electrical device 1000 of this application will be described below with appropriate reference to the accompanying drawings.

[0171] In the embodiments of this application, the secondary battery 20 is the smallest unit constituting the battery pack 100. The secondary battery 20 also includes an electrolyte 24 and a separator 23d, such as... Figure 4 As shown, the separator 23d is disposed between the positive electrode 23b and the negative electrode 23c, mainly to prevent short circuits between the positive and negative electrodes, while allowing ions to pass through. During the battery charging and discharging process, active ions Li... + The electrolyte 24 moves back and forth between the positive electrode 23b and the negative electrode 23c, intercalating and deintercalating, while conducting ions between the positive electrode 23b and the negative electrode 23c.

[0172] The positive electrode 23b includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material composition.

[0173] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0174] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0175] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0176] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0177] In some embodiments, the positive electrode 23b can be prepared by dispersing the components used to prepare the positive electrode 23b, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g. N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive current collector, and then drying, cold pressing and other processes to obtain the positive electrode 23b.

[0178] The negative electrode 23c includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0179] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0180] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0181] In some embodiments, the negative electrode film layer may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0182] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0183] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0184] In some embodiments, the negative electrode 23c can be prepared by dispersing the components used to prepare the negative electrode, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then drying, cold pressing and other processes to obtain the negative electrode 23c.

[0185] Electrolyte 24 serves to conduct ions between the positive electrode 23b and the negative electrode 23c. This application does not impose specific limitations on the type of electrolyte 24; it can be selected according to requirements.

[0186] In some embodiments, the electrolyte 24 includes an electrolyte salt and a solvent.

[0187] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0188] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0189] In some embodiments, the electrolyte 24 may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0190] In some embodiments, the secondary battery 20 includes a separator 23d. This application does not impose any particular limitation on the type of separator 23d; any known porous separator 23d with good chemical and mechanical stability can be selected.

[0191] In some embodiments, the diaphragm 23d may be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The diaphragm 23d may be a single-layer film or a multi-layer composite film, without particular limitation. When the diaphragm 23d is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0192] In some embodiments, the positive electrode 23b, the negative electrode 23c, and the separator 23d can be fabricated into electrode assembly 23 by a winding process or a stacking process.

[0193] In some implementations, such as Figure 14 As shown, the secondary battery 20 may include a housing 22. This outer packaging can be used to encapsulate the aforementioned electrode assembly 23 and electrolyte 24. The outer packaging includes a cover 21, the housing 22, and other functional components.

[0194] The cover 21 refers to a component that covers the opening of the housing 22 to isolate the internal environment of the secondary battery 20 from the external environment. The shape of the cover 21 can be adapted to the shape of the housing 22 to fit it. Optionally, the cover 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the cover 21 is not easily deformed under pressure or impact, giving the secondary battery 20 higher structural strength and improved stability. Functional components such as electrode terminals 21a can be provided on the cover 21. The electrode terminals 21a can be used to electrically connect to the electrode assembly 23 for outputting or inputting electrical energy into the secondary battery 20. In some embodiments, the cover 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the secondary battery 20 reaches a threshold. The material of the cover 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element (not shown) may be provided on the inner side of the cover 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the cover 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0195] The housing body 22a is a component used to cooperate with the cover 21 to form the internal environment of the secondary battery 20. This internal environment can accommodate the electrode assembly 23, electrolyte 24, and other components. The housing body 22a and the cover 21 can be independent components. An opening can be provided on the housing body 22a, and the cover 21 can be used to close the opening to form the internal environment of the secondary battery 20. Alternatively, the cover 21 and the housing body 22a can be integrated. Specifically, the cover 21 and the housing body 22a can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing body 22a, the cover 21 closes the housing body 22a. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0196] The housing 22 may contain one or more electrode assemblies 23. The portions of the positive electrode 23b and the negative electrode 23c that do not contain active material each constitute a tab 23a. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte 24, and the tabs 23a connect to the electrode terminals to form a current loop.

[0197] Please refer to Figure 15 The battery pack 100 includes a housing 10 and a secondary battery 20, with the secondary battery 20 housed within the housing 10. The housing 10 provides a space for the secondary battery 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, collectively defining a space for accommodating the secondary battery 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 together define the space. Alternatively, both the first portion 11 and the second portion 12 may be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0198] In the battery pack 100, there can be multiple secondary batteries 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that some of the secondary batteries 20 are connected in series while others are in parallel. Multiple secondary batteries 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple secondary batteries 20 is housed within the housing 10. Alternatively, the battery pack 100 can also consist of multiple secondary batteries 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. The battery pack 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple secondary batteries 20.

[0199] The battery pack 100 in this embodiment includes a secondary battery 20. In other embodiments, the battery pack 100 may further include any one or more of lithium-sulfur batteries, sodium-ion batteries, and magnesium-ion batteries, but is not limited thereto. The secondary battery 20 may be cylindrical, flat, cuboid, or other shapes.

[0200] In some embodiments, the battery pack 100 can be assembled into a battery module, and the number of batteries contained in the battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0201] In addition, this application also provides an electrical device 1000, which includes at least one of the secondary battery 20 and / or battery pack 100 provided in this application. The secondary battery 20 or battery pack 100 can be used as a power source for the electrical device 1000 or as an energy storage unit for the electrical device 1000. The electrical device 1000 may include mobile devices (e.g., mobile phones, laptops, etc.), 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., but is not limited thereto.

[0202] like Figure 16 As shown, the electrical device 1000 is a vehicle such as a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. A partial structural diagram of one embodiment of the electrical device is provided. A battery pack 100 is internally disposed in the electrical device 1000, and the battery pack 100 can be located at the bottom, head, or tail of the electrical device 1000. The battery pack 100 can be used to power the electrical device 1000; for example, the battery pack 100 can serve as the operating power source for the electrical device 1000. The electrical device 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery pack 100 to supply power to the motor 300, for example, to meet the power requirements of the electrical device 1000 during startup, navigation, and operation.

[0203] In some embodiments of this application, the battery pack 100 can not only serve as the operating power source for the electrical equipment 1000, but also as the driving power source for the electrical equipment 1000, replacing or partially replacing fuel oil or natural gas to provide driving power for the electrical equipment 1000.

[0204] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0205] Example 1

[0206] Preparation of the positive electrode sheet

[0207] Lithium nickel cobalt manganese oxide (LiNi 0.5 Co 0.2 Mn 0.3 O2), conductive carbon black (SP) as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder are mixed in a mass ratio of 40:1:1. N-methylpyrrolidone (NMP) as a solvent is added, and the mixture is stirred thoroughly to obtain a positive electrode slurry. The solid content of the positive electrode slurry is 60 wt%, and the viscosity at room temperature is adjusted to 15000 mPa·s. The positive electrode slurry is coated onto the surface of the positive electrode current collector, dried, and then cold-pressed using a cold rolling mill to form a positive electrode sheet. The surface density of the positive electrode powder coating is 250 mg / m². 2 The compaction density of the positive electrode sheet is 3.4 g / cm³. 3 .

[0208] Preparation of the negative electrode sheet

[0209] Artificial graphite, styrene-butadiene rubber (SBR), and sodium carboxymethyl cellulose (CMC-Na) were added to a deionized water solvent at a mass ratio of 95:2.5:2.5 and thoroughly mixed to form a negative electrode slurry. The solid content of the negative electrode slurry was 50 wt%, and the viscosity at room temperature was adjusted to 6000 mPa·s. The resulting negative electrode slurry was coated onto a negative electrode current collector, dried, and then cold-pressed (e.g., using rollers) to obtain the negative electrode sheet. The areal density of the negative electrode coating was 150 mg / m². 2 The compaction density of the negative electrode sheet is 1.6 g / m³. 3 .

[0210] Preparation of Electrolyte

[0211] In a glove box under a high-purity argon atmosphere, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are first mixed in a 1:1 mass ratio. Then, lithium hexafluorophosphate (LiPF6) is added to the organic solvent to dissolve and mix evenly to obtain a 1 mol / L LiPF6 solution. Next, vinylene carbonate (VC) is added to the electrolyte, with a mass percentage of 2 wt% in the electrolyte, thus obtaining the electrolyte.

[0212] [Septum]

[0213] A 13μm thick polyethylene membrane was used as the diaphragm.

[0214] Preparation of Functional Coatings

[0215] 10g of paraffin hydrocarbon (30 carbon atoms), 30g of ferrocene, and 200g of n-propanol were mixed and heated to 80℃. The mixture was stirred at a constant temperature until homogeneous. Then, 20g of hollow mesoporous silica microspheres with a Dv50 of 1.5μm and a pore size of 0.2μm were added to the mixture. The mixture was stirred thoroughly at 80℃ for 48h. After stirring, the mixture was filtered while hot and washed three times with hot n-propanol, followed by water washing to thoroughly remove residual paraffin hydrocarbon and ferrocene. The mixture was then placed in an oven at 50℃ for 12h to obtain functional particles with a shell, a phase change material, and a redox shuttle. The hollow mesoporous silica microspheres served as the shell, the paraffin hydrocarbon as the phase change material, and the ferrocene as the redox shuttle. Functional particles and PVDF binder are dispersed in NMP solvent at a mass ratio of 95:1 and stirred evenly to prepare a functional coating slurry. 0.5g of the functional coating slurry is then evenly sprayed onto the inner side of the shell and dried to form a functional coating.

[0216] Battery assembly

[0217] The separator, negative electrode, and positive electrode are arranged in the order of "separator-negative electrode-separator-positive electrode". One end of the positive electrode, negative electrode, and two separators is fixed to the discharge roller, and the other end is stacked together and fixed to the winding shaft. The winding shaft is rotated by a motor to wind the positive electrode, negative electrode, and two separators to obtain a wound cell. The wound cell is placed in an outer packaging, injected with prepared electrolyte, and then sealed, injected, formed, and vented to obtain a secondary battery. A heating element is provided on the outer surface of the secondary battery, and the heating element is configured to be located on opposite sides of the same wall of the casing body as the functional coating.

[0218] The main differences between Examples 2-3 and Comparative Example 1 and Example 1 are shown in Table 1.

[0219] In addition, the difference between Example 3 and Example 1 also includes the different functional coating in Example 3. Specifically, the preparation method of the functional coating in Example 3 is as follows: 0.5g of ferrocene, 2g of azelaic acid, 2g of decanediol, and 0.05g of tetrabutyl titanate are dissolved in 25ml of nonpolar solvent cyclohexane to form an oil phase; 5g of deionized water is provided, and 0.5g of polyoxyethylene sorbitan monostearate is added to the deionized water and emulsified at a speed of 6000r / min to obtain an emulsion; then the emulsion is heated to 70°C, and the following is slowly added dropwise to the emulsion: The prepared oil phase was reacted for 1 hour, then washed with water to remove surface residues, and then dried in an oven at 50°C for 12 hours to obtain functional particles with a capsule structure. Ferrocene served as the capsule core, and poly(decanediol azelaic acid) obtained from the polymer monomers azelaic acid and decanediol through the above preparation process served as the capsule wall. The functional particles and PVDF binder were dispersed in NMP solvent at a mass ratio of 95:1 and stirred evenly to prepare a functional coating slurry. 0.5 g of the functional coating slurry was then evenly sprayed onto the inner side of the shell, and dried to form a functional coating.

[0220] The difference between Comparative Example 1 and Example 1, besides the fact that Comparative Example 1 does not involve the preparation of a functional coating, also includes the different preparation of the electrolyte. Specifically, the preparation method of the electrolyte in Comparative Example 1 is as follows: In a glove box under a high-purity argon atmosphere, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are first mixed in a mass ratio of 1:1. Then, lithium hexafluorophosphate (LiPF6) is added to the organic solvent to dissolve and mix evenly to obtain a LiPF6 solution with a concentration of 1 mol / L. Then, vinylene carbonate (VC) and ferrocene are added to the electrolyte. The mass percentage of vinylene carbonate in the electrolyte is 2 wt%, and the mass percentage of ferrocene in the electrolyte is 1 wt%.

[0221] For experimental parameters and process steps not described in other embodiments and comparative examples, please refer to the description in Embodiment 1 above, which is consistent with the preceding text and will not be repeated here.

[0222] The specific testing methods for the relevant parameters in the above embodiments and comparative examples are as follows:

[0223] 1. Self-discharge test

[0224] At 25℃, a lithium-ion battery is charged to 100% SOC, and the voltage at this point is recorded as V1. After storage for 2 days, the voltage of the lithium-ion battery is tested and recorded as V2. The self-discharge voltage drop is then calculated as (V1-V2) / 48. It should be noted that when the self-discharge voltage drop is less than 0.1mV / h, the self-discharge is slight; when the self-discharge voltage drop is between 0.1mV / h and 0.15mV / h, the self-discharge is relatively severe; and when the self-discharge voltage drop is greater than 0.15mV / h, the self-discharge is severe.

[0225] 2. Phase transition temperature test

[0226] This test was conducted according to the standard ASTM D3418-2015. The specific procedure involved weighing 1–3 mg of the phase change material sample and placing it in an aluminum crucible, then covering the crucible with a lid. Under a nitrogen atmosphere, the heat flow-temperature relationship of the material was obtained through programmed temperature increases, thus yielding the corresponding phase change temperature T. m The phase transition temperature T m This can be considered as the release temperature of the redox shuttle.

[0227] 3. Potential testing of redox shuttles

[0228] By assembling Al-Cu, Al-Li, or Al-graphite half-cells, an electrochemical workstation was used to perform linear voltage scans or cyclic voltammetric scans from the open-circuit voltage at a rate of 0.1 mV / s. The scan range was 0.05 V to 5 V. The potential corresponding to the first oxidation current peak that appeared during the positive scan of the open-circuit voltage was the oxidation peak potential of the redox shuttle, and the potential corresponding to the second oxidation current peak was the decomposition potential. The potential corresponding to the first reduction current peak that appeared during the negative scan was the reduction peak potential of the redox shuttle.

[0229] Table 1: Process parameters and performance test results of Examples 1-3 and Comparative Example 1

[0230]

[0231] Based on Table 1 above, a brief analysis is as follows:

[0232] By comparing Examples 1-3 with Comparative Example 1, it can be seen that by setting the functional coating containing phase change material and redox shuttle on the wall surface of the housing body facing the electrode assembly, since the redox shuttle is located inside the phase change material, the contact between the redox shuttle and the electrolyte can be effectively reduced, thereby reducing the self-discharge level of the secondary battery.

[0233] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A secondary battery, characterized in that, The device includes an electrode assembly, an electrolyte, and a housing. The electrode assembly and the electrolyte are housed in the housing. The housing includes a housing body and a functional coating on at least a portion of the wall surface of the housing body facing the electrode assembly. The functional coating includes a phase change portion and a functional portion. The functional portion is located within the phase change portion. The phase change portion is a phase change material, and the functional portion is a redox shuttle.

2. The secondary battery according to claim 1, characterized in that, The housing also includes a cover, the housing body having a bottom wall disposed opposite to the cover and a side wall connected to the bottom wall and extending toward the cover, the functional coating being located in at least a portion of the side wall.

3. The secondary battery according to claim 1, characterized in that, The housing also includes a cover, the housing body having a bottom wall disposed opposite to the cover and a side wall connected to the bottom wall and extending toward the cover, the functional coating being located in at least a portion of the bottom wall.

4. The secondary battery according to any one of claims 1 to 3, characterized in that, The secondary battery includes a first posture, which is the posture in which the secondary battery is configured as an electrical device placed on a horizontal surface, in which the functional coating is immersed in the electrolyte.

5. The secondary battery according to claim 1, characterized in that, The secondary battery also includes a heating element located on at least a portion of the wall surface of the housing body on the side opposite to the electrode assembly.

6. The secondary battery according to claim 5, characterized in that, The heating element and the functional coating are located on opposite sides of the same wall of the housing body.

7. The secondary battery according to claim 1, characterized in that, The secondary battery also includes a liquid cooling assembly, which has a heating section and a conductive section. The heating section and the conductive section are heat-conducted through liquid in the liquid flow path of the liquid cooling assembly. The conductive section is located on at least a portion of the wall surface of the housing body on the side opposite to the electrode assembly.

8. The secondary battery according to claim 7, characterized in that, The conductive portion and the functional coating are located on opposite sides of the same wall surface of the housing body.

9. The secondary battery according to any one of claims 5 to 8, characterized in that, The heating element has a preset heating temperature, which is greater than the phase change temperature of the phase change material.

10. The secondary battery according to claim 9, characterized in that, The difference between the preset heating temperature and the phase change temperature of the phase change material is 1℃~3℃.

11. The secondary battery according to any one of claims 1-3 and 5-8, characterized in that, The phase change temperature T of the phase change material m For: 60℃≤T m ≤80℃.

12. The secondary battery according to any one of claims 1-3 and 5-8, characterized in that, The phase change material is a paraffinic hydrocarbon, a saturated fatty acid, or a polyester polymer.

13. The secondary battery according to any one of claims 1-3 and 5-8, characterized in that, The redox shuttle is one of ferrocene, piperidine oxygen radical compounds, pyridine oxygen radical compounds, quinone compounds, phenanthrene-iron complexes, bipyridine iron complexes, and their derivatives.

14. The secondary battery according to any one of claims 1-3 and 5-8, characterized in that, The secondary battery includes a voltage regulation component, the output terminal of which is electrically connected to the input terminal of the electrode assembly, and the output voltage of the voltage regulation component is greater than the oxidation peak potential of the redox shuttle.

15. The secondary battery according to claim 14, characterized in that, The voltage regulation component includes a power supply module and a control module. The power supply module is connected between the secondary battery and the external circuit, and the control module is connected between the power supply module and the secondary battery. The control module is used to respond to a voltage regulation control signal and control the output voltage of the power supply module to the secondary battery.

16. The secondary battery according to claim 15, characterized in that, The control module is also connected between the heating unit and the power module, and the control module is also used to control the preset heating temperature of the heating unit.

17. The secondary battery according to any one of claims 1-3 and 5-8, characterized in that, The thickness of the functional coating is 1μm to 10μm.

18. An electrical appliance, characterized in that, Includes the secondary battery as described in any one of claims 1 to 17.

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