A phase change electrolyte for improving battery storage effect and its preparation method and application

Abstract

The present application relates to the field of battery technology, and provides a phase change electrolyte for improving battery storage effect, and a preparation method and application thereof. Among them, the phase change electrolyte includes the following components in weight percentage: sodium salt 8% to 14%, mixed solvent 80% to 90%, additives 2% to 6%; the mixed solvent includes a high melting point solvent and a low melting point solvent in a mass ratio of (40 to 65): (20 to 45), the melting point of the high melting point solvent is greater than 15°C, and the melting point of the low melting point solvent is less than 5°C. The phase change electrolyte provided in the present application, because the mixed solvent contains a high melting point solvent and a low melting point solvent, by adjusting the type and content of the high melting point solvent and the low melting point solvent, the phase change electrolyte realizes a solid-liquid phase change at a certain temperature, and its conductivity in the solid phase and liquid phase is extremely different. Therefore, when the battery is not in use, the phase change electrolyte undergoes phase change solidification, and the conductivity is extremely low, which can reduce the battery self-discharge loss and extend the energy storage time.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a phase change electrolyte for improving battery storage effect, and a preparation method and application thereof. Background Art

[0002] As a new generation of energy storage containers, secondary batteries have the characteristics of high energy density, low memory effect, and high operating voltage. They are widely used in new energy vehicles, energy storage and other fields. However, secondary batteries have self-discharge behavior, which causes them to gradually self-discharge when not in use, resulting in a decrease in battery capacity during storage and even affecting the battery life.

[0003] Therefore, it is necessary to develop a phase change electrolyte that can reduce battery self-discharge loss to extend the battery storage time. Summary of the invention

[0004] The purpose of the present application is to provide a phase change electrolyte for improving battery storage effect and a preparation method and application thereof, aiming to solve the problem of self-discharge loss in existing secondary batteries.

[0005] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0006] In a first aspect, the present application provides a phase change electrolyte for improving battery storage effect, and the total weight of the phase change electrolyte is 100%, comprising the following components in percentage by weight:

[0007] Sodium salt 8% to 14%,

[0008] Mixed solvent 80%~90%,

[0009] Additives 2% to 6%,

[0010] The mixed solvent comprises a high melting point solvent and a low melting point solvent in a mass ratio of (40-65):(20-45), the melting point of the high melting point solvent is greater than 15°C, and the melting point of the low melting point solvent is less than 5°C.

[0011] In an embodiment, the melting point of the mixed solvent is 5°C to 45°C.

[0012] In an embodiment, the solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 45°C.

[0013] In an embodiment, the melting point of the high melting point solvent is 5°C to 25°C or 20°C to 45°C.

[0014] In an embodiment, the solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 15°C or 15°C to 30°C.

[0015] In an embodiment, the sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bis(oxalato)borate, and sodium difluorophosphate.

[0016] In an embodiment, the high melting point solvent is a sulfone solvent, and the sulfone solvent includes at least one of sulfolane, tetramethyl sulfoxide, and dimethyl sulfoxide.

[0017] In an embodiment, the low melting point solvent includes at least one of an ester solvent and an ether solvent.

[0018] In an embodiment, the additive includes fluoroethylene carbonate and propylene sulfite.

[0019] In an embodiment, the ester solvent includes propylene carbonate, and further includes at least one of ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate.

[0020] In an embodiment, the ether solvent includes at least one of ethylene glycol dimethyl ether and 1,3-dioxolane.

[0021] In an embodiment, the additive further includes at least one of vinyl sulfate, tris(trimethylsilyl)borate, and 1,3-propylene sultone.

[0022] In an embodiment, the fluoroethylene carbonate accounts for 1% to 3% of the total mass of the phase-change electrolyte.

[0023] In an embodiment, the propylene sulfite accounts for 0.2% to 1.5% of the total mass of the phase-change electrolyte.

[0024] In a second aspect, the present application provides a method for preparing a phase change electrolyte for improving battery storage effect, comprising the following steps:

[0025] Providing the sodium salt, mixed solvent and additives in the phase change electrolyte described in the present application;

[0026] The sodium salt, the mixed solvent and the additive are uniformly mixed to obtain a phase change electrolyte.

[0027] In a third aspect, the present application provides a sodium ion battery, comprising the phase change electrolyte for improving battery storage effect provided in the present application, or a phase change electrolyte prepared by the method for preparing the phase change electrolyte for improving battery storage effect provided in the present application.

[0028] In a fourth aspect, the present application provides an energy storage battery device, including a temperature control system and the sodium ion battery provided in the present application.

[0029] Compared with the prior art, this application has the following beneficial effects:

[0030] The phase change electrolyte provided in the first aspect of the present application includes a sodium salt, a mixed solvent and an additive. Since the mixed solvent contains a high melting point solvent and a low melting point solvent, the phase change electrolyte can achieve a solid-liquid phase change at a certain temperature by adjusting the types and contents of the high melting point solvent and the low melting point solvent, so that the conductivity in the solid phase and the liquid phase is very different. Therefore, when the battery is in use, the temperature control system can slightly increase the ambient temperature of the battery, so that the phase change electrolyte changes from a solid phase to a liquid phase, and the conductivity is improved, so that the battery can be used for normal charge and discharge. When the battery is not in use, the phase change electrolyte undergoes a phase change and solidifies, making the conductivity extremely low, thereby reducing the battery self-discharge loss, extending the energy storage time, and improving the storage effect of the energy storage battery.

[0031] The second aspect of the present application provides a method for preparing a phase change electrolyte for improving battery storage effect. The phase change electrolyte can be obtained by evenly mixing sodium salt, a mixed solvent and an additive. The preparation method is simple and easy to operate.

[0032] The sodium ion battery provided in the third aspect of the present application comprises the phase change electrolyte for improving the battery storage effect provided in the present application, or the phase change electrolyte prepared by the preparation method of the phase change electrolyte for improving the battery storage effect provided in the present application. Therefore, the sodium ion battery of the present application can reduce self-discharge loss, prolong energy storage time, and improve the storage effect of the energy storage battery.

[0033] The energy storage battery device provided in the fourth aspect of the present application includes a temperature control system and the sodium ion battery provided in the present application. Therefore, the energy storage battery device of the present application has a small self-discharge loss and a long energy storage time. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0036] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0037] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0038] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0039] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass described in the embodiment description of the present application can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0040] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0041] In a first aspect, an embodiment of the present application provides a phase change electrolyte for improving battery storage effect, which includes the following components in percentage by weight, based on the total weight of the phase change electrolyte being 100%:

[0042] Sodium salt 8% to 14%,

[0043] Mixed solvent 80%~90%,

[0044] Additives 2% to 6%,

[0045] The mixed solvent comprises a high melting point solvent and a low melting point solvent in a mass ratio of (40-65):(20-45), the melting point of the high melting point solvent is greater than 15°C, and the melting point of the low melting point solvent is less than 5°C.

[0046] The phase change electrolyte for improving the storage effect of a battery provided in the embodiment of the present application comprises a sodium salt, a mixed solvent and an additive. Since the mixed solvent comprises a high melting point solvent and a low melting point solvent, the type and content of the high melting point solvent and the low melting point solvent can be adjusted to make the phase change electrolyte realize a solid-liquid phase change at a certain temperature, so that the conductivity thereof in the solid phase and the liquid phase differs greatly. Therefore, when the battery is in use, the temperature control system can slightly increase the ambient temperature of the battery so that the phase change electrolyte changes from a solid phase to a liquid phase, thereby improving the conductivity, so that the battery can be used for normal charge and discharge. When the battery is not in use, the phase change electrolyte undergoes a phase change and solidifies, making the conductivity extremely low, thereby reducing the self-discharge loss of the battery, extending the energy storage time, and improving the storage effect of the energy storage battery.

[0047] In some embodiments, the melting point of the mixed solvent is 5°C to 45°C. Furthermore, the melting point of the high melting point solvent can be 5°C to 25°C or 20°C to 45°C. When the melting point of the high melting point solvent is 5°C to 25°C, by selecting different types of high melting point solvents and low melting point solvents, and adjusting the content of the high melting point solvent and the low melting point solvent, the solid-liquid phase transition temperature of the phase change electrolyte can be 5°C to 15°C, so that the battery containing the phase change electrolyte of the embodiment is suitable for use in northern regions. When the battery is not in use, the phase change electrolyte undergoes phase change and solidification, making the conductivity extremely low, thereby reducing the self-discharge loss of the battery and extending the energy storage time. When the melting point of the high melting point solvent is 20℃~45℃, by selecting different types of high melting point solvents and low melting point solvents, and adjusting the content of high melting point solvents and low melting point solvents, the solid-liquid phase change temperature of the phase change electrolyte can be made 15℃~30℃, so that the battery is suitable for use in southern regions. When the battery is not in use, the phase change electrolyte undergoes phase change and solidifies, making the conductivity extremely low, thereby reducing the battery self-discharge loss, extending the energy storage time, and improving the storage effect of the energy storage battery.

[0048] In some embodiments, the solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 45°C. The solid-liquid phase transition temperature refers to the critical temperature at which the phase change electrolyte undergoes solid-liquid transformation when the temperature changes. Further, the solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 15°C or 15°C to 30°C. When the solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 15°C, illustratively, the solid-liquid phase transition temperature can be 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, etc., so the battery containing the phase change electrolyte of the embodiment is suitable for use in northern regions. When the battery is not in use, the phase change electrolyte can automatically undergo phase change and solidification, making the conductivity of the phase change electrolyte extremely low, thereby reducing the self-discharge loss of the battery, extending the energy storage time, and improving the storage effect of the energy storage battery. When the solid-liquid phase change temperature of the phase change electrolyte is 15°C to 30°C, illustratively, the solid-liquid phase change temperature can be 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, etc., so the battery containing the phase change electrolyte of the embodiment is suitable for use in the southern region. When the battery is not in use, the phase change electrolyte can automatically undergo phase change and solidification, making the conductivity of the phase change electrolyte extremely low, thereby reducing the battery self-discharge loss, extending the energy storage time, and improving the storage effect of the energy storage battery.

[0049] In some embodiments, the sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium bis(oxalate)borate, and sodium difluorophosphate. Exemplarily, the sodium salt can be selected from sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium bis(oxalate)borate, and sodium difluorophosphate.

[0050] In some embodiments, the high melting point solvent is a sulfone solvent, and the sulfone solvent includes at least one of sulfolane (SL), tetramethyl sulfoxide, and dimethyl sulfoxide.

[0051] In some embodiments, the low melting point solvent includes at least one of an ester solvent and an ether solvent.

[0052] In some embodiments, the ester solvent includes propylene carbonate (PC), and also includes at least one of ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), and diethyl carbonate (DEC). Exemplarily, the ester solvent includes propylene carbonate and ethyl methyl carbonate, or the ester solvent includes propylene carbonate and dimethyl carbonate, or the ester solvent includes propylene carbonate and diethyl carbonate, or the ester solvent includes propylene carbonate and ethyl methyl carbonate, dimethyl carbonate.

[0053] In some embodiments, the ether solvent includes at least one of ethylene glycol dimethyl ether (DME) and 1,3-dioxolane (DOL).

[0054] In some embodiments, the additive includes fluoroethylene carbonate (FEC) and propylene sulfite (PS), wherein fluoroethylene carbonate accounts for 1% to 3% of the total mass of the phase change electrolyte, and propylene sulfite accounts for 0.2% to 1.5% of the total mass of the phase change electrolyte.

[0055] In an embodiment, the additive may further include at least one of dithiothreitol sulfate (DTD), tris(trimethylsilyl)borate (TMSB), and 1,3-propene sultone (PST).

[0056] A second aspect of the embodiment of the present application provides a method for preparing a phase change electrolyte for improving battery storage effect, comprising the following steps:

[0057] S01: providing the sodium salt, mixed solvent and additives in the phase change electrolyte of the present application;

[0058] S02: Evenly mix the sodium salt, the mixed solvent and the additive to obtain a phase change electrolyte.

[0059] The method for preparing a phase change electrolyte provided in the embodiment of the present application can obtain a phase change electrolyte by uniformly mixing a sodium salt, a mixed solvent and an additive. The preparation method is simple and easy to operate.

[0060] Since the sodium salt, mixed solvent and additive in step S01 are the sodium salt, mixed solvent and additive in the above-mentioned embodiment, in order to save the space of this specification, the sodium salt, mixed solvent and additive are not described in detail here.

[0061] A third aspect of an embodiment of the present application provides a sodium ion battery, comprising the phase change electrolyte for improving battery storage effect provided in the present application, or a phase change electrolyte prepared by the method for preparing the phase change electrolyte for improving battery storage effect provided in the present application.

[0062] The sodium ion battery provided in the embodiment of the present application comprises the phase change electrolyte for improving the battery storage effect provided in the present application, or the phase change electrolyte prepared by the preparation method of the phase change electrolyte for improving the battery storage effect provided in the present application. Therefore, the sodium ion battery of the present application can reduce self-discharge loss, prolong energy storage time, and improve the storage effect of the energy storage battery.

[0063] A fourth aspect of an embodiment of the present application provides an energy storage battery device, including a temperature control system and the sodium ion battery provided in the present application.

[0064] The energy storage battery device provided in the embodiment of the present application includes a temperature control system and the sodium ion battery provided in the present application. Therefore, the self-discharge loss of the energy storage battery device of the present application is small and the energy storage time is long.

[0065] The following describes the invention in conjunction with specific embodiments.

[0066] Example 1

[0067] This embodiment provides a phase change electrolyte for improving battery storage effect. The total weight of the phase change electrolyte is 100%, and the components are as follows:

[0068]

[0069] Among them, the high melting point solvent is sulfolane (SL, melting point is 27.4-27.8°C), the low melting point solvent is composed of 24.75% of propylene carbonate (PC, melting point is -48.8°C) and 8.25% of ethyl methyl carbonate (EMC, melting point is -55°C), and the additive is composed of 1.5% of fluoroethylene carbonate (FEC), 1% of propylene sulfite (PS), 0.5% of vinyl sulfate (DTD) and 0.5% of tris(trimethylsilyl)borate (TMSB).

[0070] Example 2

[0071] This embodiment provides a phase change electrolyte for improving battery storage effect. The total weight of the phase change electrolyte is 100%, and the components are as follows:

[0072]

[0073] Among them, the high melting point solvent is cyclopentane (SL, melting point is 27.4-27.8°C), the low melting point solvent is composed of 24.75% of propylene carbonate (PC, melting point is -48.8°C) and 8.25% of dimethyl carbonate (DMC, melting point is 4.6°C), and the additive is composed of 1.5% of fluoroethylene carbonate, 1% of propylene sulfite, 0.5% of vinyl sulfate and 0.5% of tris(trimethylsilyl)borate.

[0074] Example 3

[0075] This embodiment provides a phase change electrolyte for improving battery storage effect. The total weight of the phase change electrolyte is 100%, and the components are as follows:

[0076]

[0077]

[0078] Among them, the high melting point solvent is dimethyl sulfoxide (DMSO, melting point is 18.45°C), the low melting point solvent is composed of 24.75% of propylene carbonate (PC, melting point is -48.8°C) and 8.25% of ethyl methyl carbonate (EMC, melting point is 4.6°C), and the additive is composed of 1.5% of fluoroethylene carbonate, 1% of propylene sulfite, 0.5% of vinyl sulfate and 0.5% of tris(trimethylsilyl)borate.

[0079] Example 4

[0080] This embodiment provides a phase change electrolyte for improving battery storage effect. The total weight of the phase change electrolyte is 100%, and the components are as follows:

[0081]

[0082] Among them, the high melting point solvent is dimethyl sulfoxide (DMSO, melting point is 18.45°C), the low melting point solvent is composed of 24.75% propylene carbonate (PC, melting point is -48.8°C) and 8.25% diethyl carbonate (DMC, melting point is -73°C), and the additive is composed of 1.5% fluoroethylene carbonate, 1% propylene sulfite, 0.5% vinyl sulfate and 0.5% tris(trimethylsilyl)borate.

[0083] Comparative Example 1

[0084] This example provides an electrolyte, which includes the following components in percentage by weight, based on the total weight of the electrolyte being 100%:

[0085] NaPF6 14%,

[0086] Solvent 82.5%,

[0087] Additives 3.5%;

[0088] The solvent consists of 24.75% propylene carbonate (PC, melting point of -48.8°C) and 57.75% ethyl methyl carbonate (EMC, melting point of -55°C), and the additives consist of 1.5% fluoroethylene carbonate (FEC), 1% propylene sulfite (PS), 0.5% diethylene sulfate (DTD) and 0.5% tris(trimethylsilyl)borate (TMSB).

[0089] Comparative Example 2

[0090] This example provides an electrolyte, which includes the following components in percentage by weight, based on the total weight of the electrolyte being 100%:

[0091] NaPF6 14%,

[0092] Solvent 82.5%,

[0093] Additives 3.5%;

[0094] The solvent consists of 24.75% propylene carbonate (PC, melting point -48.8°C), 49.5% diethyl carbonate (DMC, melting point -73°C) and 8.25% ethyl methyl carbonate (EMC, melting point -55°C), and the additive consists of 1.5% fluoroethylene carbonate (FEC), 1% propylene sulfite (PS), 0.5% vinyl sulfate (DTD) and 0.5% tris(trimethylsilyl)borate (TMSB).

[0095] Related performance test analysis:

[0096] 1. The phase change electrolyte for improving battery storage effect provided in Examples 1 to 2 is solid at 20°C to 28°C and liquid at 28°C to 35°C; the phase change electrolyte for improving battery storage effect provided in Examples 3 to 4 is solid at 10°C to 18°C ​​and liquid at 18°C ​​to 25°C; the electrolyte provided in Comparative Examples 1 to 2 is liquid at 28°C to 35°C or 10°C to 25°C; it indicates that the electrolyte provided in Comparative Examples 1 to 2 cannot undergo phase change at a certain temperature, while the phase change electrolyte for improving battery storage effect provided in the embodiments of the present application can undergo solid-liquid phase change at a certain temperature.

[0097] 2. The phase change electrolyte for improving the battery storage effect provided in Examples 1 to 4 and the electrolyte provided in Comparative Examples 1 to 2 were respectively injected into the same batch of soft-pack sodium ion batteries. After the capacity was divided, the batteries of Examples 1 to 2 and Comparative Examples 1 to 2 were stored at 25° C. for 7 days, 14 days and 28 days, the voltage was tested at 30° C., and the K value was calculated. The test results are shown in Table 1 below. The batteries of Examples 3 to 4 and Comparative Examples 1 to 2 were stored at 15° C. for 7 days, 14 days and 28 days, the voltage was tested at 30° C., and the K value was calculated. The test results are shown in Table 2 below.

[0098] Table 1 (Batteries stored at 25°C)

[0099]

[0100] Table 2 (Batteries stored at 15°C)

[0101]

[0102] It can be seen from Table 1 and Table 2 that the storage voltage drop and K value of the phase change electrolyte for improving the battery storage effect provided by Examples 1 to 4 are smaller than the storage voltage drop and K value of the electrolyte provided by Comparative Examples 1 to 2, indicating that the phase change electrolyte for improving the battery storage effect provided by the embodiments of the present application undergoes a solid-liquid phase change at a certain temperature, so that the conductivity of the battery in the solid phase and the liquid phase differs greatly, so that when the battery is not in use, the phase change electrolyte undergoes a phase change and solidifies, significantly reducing the conductivity, thereby reducing the battery self-discharge loss, extending the energy storage time, and improving the storage effect of the energy storage battery.

[0103] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A phase change electrolyte for improving battery storage effect, characterized in that: The solid-liquid phase transition temperature of the phase change electrolyte is 5°C to 30°C; based on the total weight of the phase change electrolyte being 100%, the phase change electrolyte comprises the following components in percentage by weight: Sodium salt 8% to 14%, Mixed solvent 80%~90%, Additives 2% to 6%, The mixed solvent comprises a high melting point solvent and a low melting point solvent in a mass ratio of (40-65):(20-45), the melting point of the mixed solvent is 5°C-45°C, and the melting point of the low melting point solvent is less than 5°C; The melting point of the high melting point solvent is n, wherein 15°C < n ≤ 45°C; The high melting point solvent is a sulfone solvent; The sulfone solvent includes at least one of sulfolane, tetramethyl sulfoxide and dimethyl sulfoxide.

2. The phase change electrolyte for improving battery storage effect according to claim 1, characterized in that: The sodium salt includes at least one of sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bis(oxalato)borate, and sodium difluorophosphate; And / or, the low melting point solvent includes at least one of an ester solvent and an ether solvent; And / or, the additive includes fluoroethylene carbonate and propylene sulfite.

3. The phase change electrolyte for improving battery storage effect as claimed in claim 2, characterized in that: The ester solvent includes propylene carbonate, and also includes at least one of ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate; And / or, the ether solvent includes at least one of ethylene glycol dimethyl ether and 1,3-dioxolane; And / or, the additive further includes at least one of vinyl sulfate, tris(trimethylsilyl)borate, and 1,3-propylene sultone.

4. The phase change electrolyte for improving battery storage effect as claimed in claim 3, characterized in that: The fluoroethylene carbonate accounts for 1% to 3% of the total mass of the phase change electrolyte; And / or, the propylene sulfite accounts for 0.2% to 1.5% of the total mass of the phase-change electrolyte.

5. A method for preparing a phase change electrolyte for improving battery storage effect, characterized in that: The following steps are involved: Providing a sodium salt, a mixed solvent and an additive in a phase change electrolyte for improving battery storage effect as claimed in any one of claims 1 to 4; The sodium salt, the mixed solvent and the additive are uniformly mixed to obtain a phase change electrolyte.

6. A sodium ion battery, characterized in that: A phase change electrolyte for improving battery storage effect comprising the phase change electrolyte for improving battery storage effect as described in any one of claims 1 to 4, or a phase change electrolyte prepared by the method for preparing the phase change electrolyte for improving battery storage effect as described in claim 5.

7. An energy storage battery device, characterized in that: It comprises a temperature control system and the sodium ion battery according to claim 6.

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