Sodium battery, method of forming a sodium battery, and electric device

Abstract

The sodium battery, a method for forming a sodium battery, and an electrical device. Based on the total volume of gas inside the sodium battery housing, the total volume ratio of the inert gas is 15% to 50%. In the sodium battery, an inert gas is injected into the sodium battery housing at the stage after the initial injection of the electrolyte is completed and before the sodium battery forming process begins, and the sodium battery is formed under an atmosphere containing the inert gas inside the sodium battery housing, thereby improving the initial Coulomb efficiency of the sodium battery.

Description

Technology Field

[0001] This application incorporates Chinese Patent Application No. 2024103023155, filed on March 15, 2024, titled "Sodium Battery, Method for Forming a Sodium Battery and Electric Device," the entire contents of which are incorporated into this application by means of citation.

[0002] The present application relates to the field of secondary battery technology, and in particular to sodium batteries, a method for forming a sodium battery, and an electric device. Background Technology

[0003] Recently, rechargeable batteries are being widely applied in various fields, including energy storage power systems such as hydroelectric, thermal, wind, and solar power plants, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, and aerospace. As rechargeable batteries become more widely applied, higher demands are being placed on their recyclability and service life.

[0004] Sodium batteries have the advantages of being abundant, inexpensive, and safe, but their additional applications are limited due to their low initial Coulomb efficiency. The problem to be solved

[0005] This application has been made in consideration of the above-mentioned problem and aims to provide a sodium battery having high initial Coulomb efficiency. means of solving the problem

[0006] The first aspect of the present application provides a sodium battery, wherein the total volume ratio of the inert gas is 15% to 50% based on the total volume of the gas within the sodium battery housing.

[0007] In any embodiment, the total volume ratio of the inert gas is 30% to 45% based on the total volume of the gas in the sodium battery housing.

[0008] In any embodiment, the inert gas comprises one or more of argon, helium, and nitrogen.

[0009] In any embodiment, the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, the positive film layer comprises a positive active material, and the positive active material comprises a polyanionic compound.

[0010] In any embodiment, the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr.

[0011] In any embodiment, the polyanionic compound comprises at least one of sodium iron phosphate pyrophosphate, sodium vanadium phosphate, and sodium iron phosphate.

[0012] In any embodiment, the sodium battery includes a sodium battery without a negative electrode and a sodium metal battery.

[0013] A second aspect of the present application provides a method for forming a sodium battery, comprising the steps of: injecting an electrolyte into a sodium battery housing; injecting an inert gas into a sodium battery housing; and forming the sodium battery; wherein, after the inert gas injection is completed and before the sodium battery forming process begins, the method does not include the step of performing vacuum suction on the sodium battery housing.

[0014] According to research, during the initial charging, or formation, of a sodium battery, active sodium detached from the positive electrode active material easily combines with reactive gases such as oxygen and carbon dioxide attached to the surface of the positive electrode active material, causing some loss of the detached active sodium, which reduces the initial discharge capacity of the battery and degrades the initial Coulomb efficiency of the sodium battery. The formation method of the sodium battery of the present application involves injecting an inert gas into the battery housing after the electrolyte injection is completed and before the sodium battery formation process begins, so that the formation of the sodium battery proceeds under an atmosphere containing the inert gas within the battery housing. The inert gas within the housing can dilute the concentration of reactive gases adsorbed on the surface of the positive electrode active material and inhibit the combination of the detached active sodium with the reactive gases during the formation process, thereby reducing the loss of active sodium and improving the initial Coulomb efficiency of the sodium battery.

[0015] In any embodiment, the inert gas comprises one or more of argon, helium, and nitrogen.

[0016] In any embodiment, the pressure of the inert gas when injecting the inert gas is 25 kPa to 100 kPa.

[0017] When injecting an inert gas, if the pressure of the inert gas is within the range described above, production efficiency can be ensured while preventing the battery cell from being deformed due to excessive pressure of the injected gas.

[0018] In any embodiment, the injection time when injecting the inert gas is 2 to 15 seconds.

[0019] If the injection time when injecting the inert gas is within the range described above, the sodium battery has good initial Coulomb efficiency and production efficiency.

[0020] In any embodiment, an inert gas is injected within 1 to 6 hours after the electrolyte injection is completed.

[0021] After injecting the electrolyte into the sodium battery housing, the positive active material of the sodium battery is infiltrated into the electrolyte. When the electrolyte is used as a medium, oxygen adsorbed on the surface of the positive active material is prone to oxidizing the positive active material, causing the positive active material to change into a desodium state. This results in an irreversible loss of active sodium, which contributes to capacity, thereby reducing the total amount of active sodium that can be detached from the positive active material during the sodium battery formation process, which reduces the initial charge capacity of the sodium battery and worsens the initial Coulomb efficiency of the sodium battery. If an inert gas is injected within 1 to 6 hours after the completion of the electrolyte injection, it is possible to allow some of the gas adsorbed on the surface of the positive active material after the electrolyte injection to be discharged on its own. Furthermore, under conditions where the electrolyte is used as a medium, the reaction occurring between the positive active material and the oxygen adsorbed on the surface of the positive active material can be reduced, thereby reducing the loss of active sodium and improving the initial Coulomb efficiency of the sodium battery.

[0022] In any embodiment, the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, the positive film layer comprises a positive active material, and the positive active material comprises a polyanionic compound.

[0023] In any embodiment, the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr.

[0024] In any embodiment, the polyanionic compound comprises at least one of sodium iron phosphate pyrophosphate, sodium vanadium phosphate, and sodium iron phosphate.

[0025] After injecting the electrolyte into the sodium battery housing, the aforementioned positive active material is prone to oxidation to a desodium state by oxygen when the electrolyte acts as a medium, resulting in irreversible loss of active sodium; furthermore, during the initial charging process, the active sodium detached from the positive active material readily combines with reactive gases, causing additional irreversible loss of active sodium and lowering the initial Coulomb efficiency of the sodium battery. If an inert gas is injected into the battery housing after the initial liquid injection, the inert gas within the housing can dilute the concentration of reactive gases adsorbed on the surface of the positive active material and suppress related chemical reactions that cause loss of active sodium, which is advantageous for improving the initial Coulomb efficiency of the sodium battery.

[0026] In any embodiment, the sodium battery includes a sodium battery without a negative electrode and a sodium metal battery.

[0027] After the initial charging of a sodium battery without a negative electrode and a sodium metal battery is completed, active sodium ions detached from the positive active material are reduced and deposited on the sodium metal layer at the negative electrode. The highly reducing sodium metal reacts easily with oxygen within the sodium battery housing, causing irreversible loss of active sodium and severely degrading the initial Coulomb efficiency of the battery. After the electrolyte injection is completed, an inert gas is injected into the battery housing so that the formation of the sodium battery proceeds under an atmosphere containing the inert gas within the battery housing, thereby significantly improving the initial Coulomb efficiency of the sodium battery without a negative electrode and the sodium metal battery.

[0028] A third aspect of the present application also provides an electric device comprising a sodium battery of the first aspect or a sodium battery manufactured using the formation method of the second aspect. Brief explanation of the drawing

[0029] FIG. 1 is a schematic diagram of a sodium battery according to one embodiment of the present application; FIG. 2 is an exploded view of a sodium battery of one embodiment of the present application illustrated in FIG. 1; FIG. 3 is a schematic diagram of a battery module of one embodiment of the present application; FIG. 4 is a schematic diagram of a battery pack according to one embodiment of the present application; FIG. 5 is an exploded view of a battery pack of one embodiment of the present application illustrated in FIG. 4; FIG. 6 is a schematic diagram of an electric device using a sodium battery as a power source according to one embodiment of the present application. Specific details for implementing the invention

[0030] Hereinafter, embodiments of the sodium battery, the method for forming the sodium battery, and the electrical device of the present application are specifically disclosed with appropriate reference to the detailed description of the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of known matters may be omitted, and repetitive descriptions of substantially identical structures may be omitted. This is intended to avoid making the following description unnecessarily long and to facilitate understanding by those skilled in the art. Furthermore, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the contents described in the claims.

[0031] The “ranges” disclosed in this application are limited in the form of lower and upper limits, and a given range is limited by selecting one lower limit and one upper limit, and the selected lower limit and upper limit limit the boundaries of a particular range. A range limited in this way may or may not include end values ​​and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a single range. For example, if ranges 60–120 and 80–110 are listed for a specific parameter, it is expected to be understood as ranges 60–110 and 80–120. In addition, if minimum range values ​​1 and 2 are listed and maximum range values ​​3, 4, and 5 are listed, the following ranges 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5 may all be expected. In this application, unless otherwise stated, numeric ranges “a–b” represent a simplified expression of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" indicates that all real numbers between "0 to 5" are listed in this document, and "0 to 5" is merely an abbreviated expression for such numerical combinations. Also, specifying that any parameter is an integer greater than 2 is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0032] Unless otherwise specified, all embodiments and optional embodiments of the present application may be combined with one another to form a new technical solution.

[0033] Unless otherwise specified, all technical features and optional technical features of the present application can be combined with one another to form a new technical solution.

[0034] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, and are preferably performed sequentially. For example, the statement that the method comprises steps (a) and (b) indicates that the method may comprise steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the expression stating that the method may also comprise step (c) indicates that step (c) may be added to the method in any order, and for example, the method may comprise steps (a), (b), and (c), steps (a), (c), and (b), or steps (c), (a), and (b).

[0035] Unless otherwise specified, the terms "comprehensive" and "include" as used in this application represent open expressions, which may also be closed expressions. For example, the "comprehensive" and "include" may also encompass or include other components not listed, or may only encompass or include the listed components.

[0036] Unless otherwise specified, the term “or” in this application is inclusive. For example, the expression “A or B” indicates “A, B or both A and B”. More specifically, any one of the following conditions all satisfy the “A or B” condition: a condition where A is true (or exists) and B is false (or does not exist); a condition where A is false (or does not exist) and B is true (or exists); or a condition where both A and B are true (or exist).

[0037] Although sodium batteries have the advantages of being inexpensive, resource-rich, and safe, they exhibit relatively low Coulomb efficiency during the first cycle of charging and discharging, which affects their further applications. The formation process is one of the critical processes in the production and manufacturing of sodium batteries. When sodium batteries are formed, gases such as oxygen and carbon dioxide present in the housing cause irreversible loss of the active sodium provided by the cathode active material, which will degrade the initial Coulomb efficiency of the sodium battery.

[0038] [Sodium Battery Marsization Method]

[0039] In light of this, the present application provides a method for forming a sodium battery, comprising the steps of: injecting an electrolyte into a sodium battery housing; injecting an inert gas into a sodium battery housing; and forming the sodium battery; wherein, after the inert gas injection is completed and before the sodium battery forming process begins, the method does not include the step of performing vacuum suction on the sodium battery housing.

[0040] In this document, the term "sodium battery housing" refers to an external packaging material for an electrode assembly composed of a positive electrode, a negative electrode, and a separator.

[0041] In some embodiments, the housing includes a cylindrical housing, a rectangular housing, and a softpack housing.

[0042] In this document, the term "inert gas" refers to a gas that is chemically very stable and difficult to react with other substances.

[0043] In this invention, the term "composition" refers to the process of completing the assembly of the electrode assembly and the battery housing, injecting the electrolyte into the sodium battery housing for the first time, and then performing the first charging.

[0044] In this document, the term "vacuum suction" refers to reaching a vacuum state by removing gas from a container or system and lowering the gas pressure within the container or system to within a certain range.

[0045] In this document, the term "initial Coulomb efficiency" refers to the ratio of the initial discharge capacity to the initial charge capacity of a full battery.

[0046] In some embodiments, the inert gas includes one or more of argon, helium, and nitrogen.

[0047] According to research, during the initial charging, or formation, of a sodium battery, active sodium detached from the positive electrode active material easily combines with reactive gases such as oxygen and carbon dioxide attached to the surface of the positive electrode active material, causing some loss of the detached active sodium, which reduces the initial discharge capacity of the battery and degrades the initial Coulomb efficiency of the sodium battery. The formation method of the sodium battery of the present application involves injecting an inert gas into the battery housing after the electrolyte injection is completed and before the sodium battery formation process begins, so that the formation of the sodium battery proceeds under an atmosphere containing the inert gas within the battery housing. The inert gas within the housing can dilute the concentration of reactive gases adsorbed on the surface of the positive electrode active material and inhibit the combination of the detached active sodium with the reactive gases during the formation process, thereby reducing the loss of active sodium and improving the initial Coulomb efficiency of the sodium battery.

[0048] In some embodiments, the step of injecting an electrolyte into a sodium battery housing includes vacuuming the sodium battery housing to -5Kpa to 30Kpa to inject the electrolyte into the sodium battery housing.

[0049] Before injecting the electrolyte after vacuuming the sodium battery housing, the electrolyte can be driven into the housing by utilizing the pressure difference between the inside and outside of the sodium battery housing, but even with vacuum suction, reactive gases adsorbed on the surface of the positive active material cannot be removed. After the electrolyte injection is completed and before the sodium battery formation process begins, an inert gas is injected into the battery housing so that the formation of the sodium battery proceeds under an atmosphere containing the inert gas within the battery housing, which can serve to dilute the concentration of the reactive gas and suppress the reaction of the reactive gas with the active sodium detached from the positive active material during the formation process. Compared to vacuum suction, injecting an inert gas into the sodium battery housing can improve the initial Coulomb efficiency of the sodium battery.

[0050] In some embodiments, the pressure of the inert gas when injecting the inert gas is 25 kPa to 100 kPa.

[0051] In some embodiments, the pressure of the inert gas when injecting the inert gas is 25 kPa, 40 kPa, 55 kPa, 70 kPa, 85 kPa, 100 kPa, or any value between these.

[0052] When injecting an inert gas, if the pressure of the inert gas is within the range described above, production efficiency can be ensured while preventing the battery cell from being deformed due to excessive pressure of the injected gas.

[0053] In some embodiments, the injection time when injecting an inert gas is 2 to 15 seconds.

[0054] In some embodiments, the injection time when injecting the inert gas is 2 seconds, 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, or any number between these.

[0055] If the injection time when injecting the inert gas is within the range described above, the sodium battery has good initial Coulomb efficiency and production efficiency.

[0056] In some embodiments, an inert gas is injected within 1 to 6 hours after the electrolyte injection is completed.

[0057] In some embodiments, an inert gas is injected at 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, or any value in between after the electrolyte injection is completed.

[0058] After injecting the electrolyte into the sodium battery housing, the positive active material of the sodium battery is infiltrated into the electrolyte. When the electrolyte is used as a medium, oxygen adsorbed on the surface of the positive active material is prone to oxidizing the positive active material, causing the positive active material to change into a desodium state. This results in an irreversible loss of active sodium, which contributes to capacity, thereby reducing the total amount of active sodium that can be detached from the positive active material during the sodium battery formation process, which reduces the initial charge capacity of the sodium battery and worsens the initial Coulomb efficiency of the sodium battery. If an inert gas is injected within 1 to 6 hours after the completion of the electrolyte injection, it is possible to allow some of the gas adsorbed on the surface of the positive active material after the electrolyte injection to be discharged on its own. Furthermore, under conditions where the electrolyte is used as a medium, the reaction occurring between the positive active material and the oxygen adsorbed on the surface of the positive active material can be reduced, thereby reducing the loss of active sodium and improving the initial Coulomb efficiency of the sodium battery.

[0059] In some embodiments, the method for forming a sodium battery also includes a step of leaving it for 6 to 36 hours.

[0060] In some embodiments, a method for forming a sodium battery comprises the steps of: injecting an electrolyte into a sodium battery housing; letting it stand for 6 to 36 hours; injecting an inert gas into the sodium battery housing; and forming the sodium battery; wherein, after the inert gas injection is completed and before the sodium battery forming process begins, the method does not include the step of performing vacuum suction on the sodium battery housing.

[0061] In some embodiments, a method for forming a sodium battery comprises the steps of: injecting an electrolyte into a sodium battery housing; injecting an inert gas into a sodium battery housing; leaving it to stand for 6 to 36 hours; and forming the sodium battery, wherein, after the inert gas injection is completed and before the sodium battery forming process begins, the method does not include the step of performing vacuum suction on the sodium battery housing.

[0062] After the electrolyte is first injected into the sodium battery housing, it must be left to stand for a long time to allow the electrolyte to sufficiently infiltrate the positive electrode, negative electrode, and separator. If an inert gas is injected into the sodium battery housing after the electrolyte injection is completed and before the long-term standing begins, it prevents the reaction that occurs between the positive active material and oxygen adsorbed on the surface of the positive active material due to the long-term standing under conditions where the electrolyte is used as a medium, thereby reducing the loss of active sodium and improving the initial Coulomb efficiency of the sodium battery.

[0063] In some embodiments, the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, and the positive film layer comprises a positive active material.

[0064] In some embodiments, the positive electrode active material may be a positive electrode active material for batteries known in the art. For example, the positive electrode active material may comprise at least one material selected from Prussian blue analogs, sodium-containing phosphates, sodium-containing transition metal oxides, and modified compounds thereof. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. Such positive electrode active materials may be used alone or in combination of two or more. Here, the Prussian blue analog is Na x P[R(CN)6] δ ·zH2O, where P and R are each independently selected from at least one of the transition metal elements, and 0 <x≤2, 0<δ≤1 및 0≤z≤10이고; 나트륨 함유 인산염은 Na b Me c (PO4) d O2X, where A is one or more of H, Li, Na, K, and NH4, Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu, and Zn, X is one or more of F, Cl, and Br, and 0 <b≤4, 0<c≤2, 1≤d≤3이며; 나트륨 함유 전이금속 산화물은 Na a M b N c Fe d Mn e O2, and M and N include at least one of Sc, Ti, V, Cr, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W and Pb, and 0.05≤b≤0.2, 0.2≤c≤0.3, 0.2≤d≤0.3, 0.3≤e≤0.4, 0.75≤a / (b+c+d+e)≤1.

[0065] In some embodiments, the positive active material includes a polyanionic compound.

[0066] In this document, the term "polyanionic compound" refers to a collective term for a series of compounds containing tetrahedral and polyhedral anionic structural units and having a three-dimensional network structure formed by being connected by strong covalent bonds.

[0067] In some embodiments, the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr.

[0068] In this institution, the term "phosphate" refers to PO4 3- It refers to.

[0069] In this document, the term "pyrophosphate" refers to P2O7 4 - It refers to.

[0070] In some embodiments, the polyanionic compound comprises at least one of sodium iron phosphate, sodium vanadium phosphate, and sodium iron phosphate.

[0071] The aforementioned positive electrode active material is prone to oxidation to a desodium state by oxygen when the electrolyte acts as a medium, resulting in irreversible loss of active sodium; furthermore, during the initial charging process, the active sodium detached from the positive electrode active material readily combines with reactive gases, causing additional irreversible loss of active sodium and lowering the initial Coulomb efficiency of the sodium battery. When an inert gas is injected into the battery housing after the initial liquid injection, the inert gas in the housing can dilute the concentration of reactive gases adsorbed on the surface of the positive electrode active material and suppress related chemical reactions that cause loss of active sodium, thereby improving the initial Coulomb efficiency of the sodium battery.

[0072] In some embodiments, sodium batteries include sodium batteries without a negative electrode and sodium metal batteries.

[0073] In this invention, the term "sodium battery without a negative electrode" refers to a battery configured such that a negative electrode active material layer is not actively installed on the negative electrode side during the battery manufacturing process. For example, a negative electrode active material layer is not formed by installing a sodium metal or carbonaceous active material layer at the negative electrode location through processes such as coating or deposition during the battery manufacturing process. During initial charging, sodium ions obtain electrons from the positive electrode side and are deposited as metallic sodium on the surface of the current collector to form a sodium metal phase. During discharge, the metallic sodium is converted back into sodium ions and can return to the positive electrode, thereby enabling a cycle of charging and discharging.

[0074] In this document, the term "sodium metal battery" refers to a secondary battery manufactured by pre-depositing sodium metal or an alloy thereof on the negative electrode during the battery manufacturing process.

[0075] After the initial charging of a sodium battery without a negative electrode and a sodium metal battery is completed, active sodium ions detached from the positive active material are reduced and deposited on the sodium metal layer at the negative electrode. The highly reducing sodium metal reacts easily with oxygen within the sodium battery housing, causing irreversible loss of active sodium and severely degrading the initial Coulomb efficiency of the battery. After the electrolyte injection is completed, an inert gas is injected into the battery housing so that the formation of the sodium battery proceeds under an atmosphere containing the inert gas within the battery housing, thereby significantly improving the initial Coulomb efficiency of the sodium battery without a negative electrode and the sodium metal battery.

[0076] [Sodium Battery]

[0077] The present application also provides a sodium battery, wherein, based on the total volume of gas within the sodium battery housing, the total volume ratio of the inert gas within the sodium battery housing is 15% to 50%.

[0078] In some embodiments, the inert gas includes one or more of argon, helium, and nitrogen.

[0079] In this application, the total volume ratio of inert gas within the sodium battery housing may be tested using methods known in the art, for example, using gas component analysis—gas chromatography, with the detection standard being GB / T 9722-2006. Test principle: After the sample and its measured components are vaporized, they enter a chromatography column along with a carrier gas (typically oxygen). Separation is performed by utilizing differences in physicochemical performance, such as adsorption, dissolution, desorption, or elution between gas-solid or gas-liquid phases, which create differences in the migration speeds of the components within the column. Each separated component exits the chromatography column in sequence, enters a detector, and records the chromatography column and corresponding data by a data processing system. The retention value and the chromatographic peak area or corresponding peak height value of each component serve as qualitative or quantitative criteria, respectively. Operation method: Sampling volume: 1 mL; The splitting ratio is 5:1, and a TCD (thermal conductivity detector) is used. After equilibrating the device, a quantified amount of gas is extracted from the sodium battery housing using a gas injection syringe, the gas is injected through the injection port, and GC-TCD analysis is performed to obtain the volume ratio of each inert gas, and the total volume ratio of the inert gas is calculated based on the total volume of gas in the sodium battery housing.

[0080] In some embodiments, based on the total volume of gas in the sodium battery housing, the total volume ratio of the inert gas in the sodium battery housing is 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any value between these.

[0081] In any embodiment, the total volume ratio of the inert gas is 30% to 45% based on the total volume of the gas in the sodium battery housing.

[0082] In some embodiments, the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, and the positive film layer comprises a positive active material.

[0083] In some embodiments, the positive electrode active material may be a positive electrode active material for batteries known in the art. For example, the positive electrode active material may comprise at least one material selected from Prussian blue analogs, sodium-containing phosphates, sodium-containing transition metal oxides, and modified compounds thereof. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. Such positive electrode active materials may be used alone or in combination of two or more. Here, the Prussian blue analog is Na x P[R(CN)6] δ ·zH2O, where P and R are each independently selected from at least one of the transition metal elements, and 0 <x≤2, 0<δ≤1 및 0≤z≤10이고; 나트륨 함유 인산염은 Na b Me c (PO4) d O2X, where A is one or more of H, Li, Na, K, and NH4, Me is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu, and Zn, X is one or more of F, Cl, and Br, and 0 <b≤4, 0<c≤2, 1≤d≤3이며; 나트륨 함유 전이금속 산화물은 Na a M b N c Fe d Mn eO2, and M and N include at least one of Sc, Ti, V, Cr, Co, Ni, Cu, Zn, Zr, Nb, Mo, Sn, Hf, Ta, W and Pb, and 0.05≤b≤0.2, 0.2≤c≤0.3, 0.2≤d≤0.3, 0.3≤e≤0.4, 0.75≤a / (b+c+d+e)≤1.

[0084] In some embodiments, the positive active material includes a polyanionic compound.

[0085] In some embodiments, the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr.

[0086] In some embodiments, the polyanionic compound comprises at least one of sodium iron phosphate, sodium vanadium phosphate, and sodium iron phosphate.

[0087] In some embodiments, sodium batteries include sodium batteries without a negative electrode and sodium metal batteries.

[0088] [Polar Side]

[0089] The positive plate typically comprises a positive current collector and a positive film layer installed on at least one surface of the positive current collector, and the positive film layer comprises a positive active material.

[0090] For example, the positive current collector has two surfaces facing each other in its thickness direction, and the positive film layer is installed on any one or both of the two surfaces facing each other of the positive current collector.

[0091] In some embodiments, the positive current collector may use 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 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 (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0092] In some embodiments, the anode film layer may also optionally include an adhesive. For example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0093] In some embodiments, the anode film layer also optionally comprises a conductor. For example, the conductor may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0094] In some embodiments, an anode piece can be manufactured in the following manner: the components used in the above-described anode piece manufacturing, e.g., an anode active material, a conductor, an adhesive, and any other components are dispersed in a solvent (e.g., N-methylpyrrolidone) to form an anode slurry; the anode slurry is coated onto an anode current collector, and the anode piece can be obtained directly through processes such as drying and cold pressing.

[0095] [Cathode]

[0096] In some embodiments, the secondary battery is a battery without a negative electrode.

[0097] In some embodiments, the cathode piece includes a cathode current collector.

[0098] In some embodiments, to improve battery performance, some common materials that can be used as negative electrode active materials, such as carbonaceous materials, metal oxides, alloys, etc., may be installed on the negative side of a negative electrode-less battery. These materials have a certain capacity, but because the amount of these materials is relatively small, they are not used as the main negative electrode active material of the battery and are not considered to form a negative electrode active material layer that serves as a lithium insertion or sodium insertion layer, and the secondary battery thus configured can still be considered a negative electrode-less battery.

[0099] In some embodiments, the cathode piece comprises a cathode current collector and a cathode film layer installed on at least one surface of the cathode current collector, and the cathode film layer comprises a cathode active material.

[0100] As an example, the cathode current collector has two surfaces facing each other in its thickness direction, and the cathode film layer can be installed on any one or both of the two surfaces facing each other of the cathode current collector.

[0101] In some embodiments, the negative current collector may use a metal foil or a composite current collector. For example, copper foil or aluminum 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, aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0102] In some embodiments, the negative electrode active material may be a negative electrode active material for batteries known in the art. For example, the negative electrode active material may include at least one of materials such as synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of single-element silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of single-element tin, tin oxide, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials may also be used. Such negative electrode active materials may be used alone or in combination of two or more.

[0103] In some embodiments, the cathode film layer also optionally comprises an adhesive. For example, the adhesive 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).

[0104] In some embodiments, the cathode film layer also optionally comprises a conductor. For example, the conductor may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0105] In some embodiments, the cathode film layer also optionally includes other auxiliary agents such as a thickener (e.g., sodium carboxymethylcellulose (CMC-Na)).

[0106] In some embodiments, a cathode plate can be manufactured in the following manner: the components used in the above-described manufacturing of the cathode plate, e.g., a cathode active material, a conductor, an adhesive, and any other components are dispersed in a solvent (e.g., deionized water) to form a cathode slurry; the cathode slurry is coated onto a cathode current collector and the cathode plate can be obtained directly through processes such as drying and cold pressing.

[0107] [Electrolyte]

[0108] The electrolyte serves to conduct ions between the anode and the cathode. The present application has no specific limitations on the type of electrolyte and can be selected according to demand. For example, the electrolyte may be in a liquid, gel, or completely solid state.

[0109] In some embodiments, the electrolyte uses an electrolyte solution. The electrolyte solution comprises an electrolyte salt and a solvent.

[0110] In some embodiments, the electrolyte comprises an electrolyte salt, and the electrolyte salt is selected from at least one of NaPF6, NaBF4, NaN(SO2F)2(NaFSI), NaClO4, NaAsF6, NaB(C2O4)2(NaBOB), NaBF2(C2O4)(NaDFOB), NaN(SO2RF)2, and NaN(SO2F)(SO2RF), wherein RF is C b F 2b +1 It is represented as , and b is an integer between 1 and 10, optionally an integer between 1 and 3.

[0111] In some embodiments, the electrolyte salt is selected from one or more of NaPF6, NaN(SO2F)2, NaN(CF3SO2)2, NaB(C2O4)2, and NaBF2(C2O4). In some embodiments, the electrolyte salt is selected from one or more of NaPF6, NaN(SO2RF)2, and NaBF2(C2O4). In some embodiments, RF is -CF3, -C2F5, or -CF2CF2CF3.

[0112] In some embodiments, the electrolyte comprises a solvent, and the solvent comprises at least one of a chain carbonate, a chain carboxylate, a cyclic carbonate, an ether-based solvent, a sulfone-based solvent, and a nitrile-based solvent. In some embodiments, the chain carbonate comprises at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), methyl isopropyl carbonate (MIPC), methyl butyl carbonate, ethyl propyl carbonate, dipropyl carbonate, and dibutyl carbonate. In some embodiments, the chain carbonate comprises at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and methyl propyl carbonate (MPC). In some embodiments, the chain-type carboxylate comprises at least one of methyl formate (MF), ethyl formate (EF), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), ethyl butyrate (EB), methyl acetate (MA), ethyl acetate (EA), and propyl acetate (PA). In some embodiments, the chain-type carboxylate comprises at least one of methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl acetate (MA), ethyl acetate (EA), and propyl acetate (PA). In some embodiments, the ether-based solvent comprises at least one of dioxolane (DOL), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2Me-THF), tetrahydropyran (THP), 1,2-dimethoxyethane (DME), diethylene glycol dimethyl ether (DG), 1,2-diethoxyethane, and 1,2-dibutoxyethane.

[0113] In some embodiments, the electrolyte also optionally includes additives. For example, the additives may include a cathode film-forming additive and an anode film-forming additive, and may also include additives that can improve specific performance of the battery, such as an additive that improves the overcharge performance of the battery, or an additive that improves the high or low temperature performance of the battery.

[0114] [Separator]

[0115] In some embodiments, the secondary battery also includes a separator. The present application makes no particular limitation on the type of separator and any known porous separator having excellent chemical and mechanical stability may be used.

[0116] In some embodiments, the material of the separator may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and there are no particular limitations thereon. If the separator is a multilayer composite film, the material of each layer may be the same or different, and there are no particular limitations thereon.

[0117] In some embodiments, the anode, cathode, and separator can be manufactured into an electrode assembly through a winding process or a lamination process.

[0118] In some embodiments, the secondary battery may include an external packaging material. The external packaging material may be used to package the electrode assembly and electrolyte described above.

[0119] In some embodiments, the external packaging material of the secondary battery may be a rigid shell, such as a rigid plastic shell, an aluminum shell, a steel shell, etc. The external packaging material of the secondary battery may also be a soft pack, such as a pouch-type soft pack. The material of the soft pack may be plastic, and examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0120] In the present application, the shape of the sodium battery includes, but is not limited to, a cylindrical, rectangular, or any other shape. For example, FIG. 1 is a sodium battery (5) with a rectangular structure as an example.

[0121] In some embodiments, referring to FIG. 2, the outer packaging may include a housing body (51) and a cover plate (53). Here, the housing body (51) may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate are enclosed to form a receiving chamber. The housing body (51) has an opening communicating with the receiving chamber, and a cover plate (53) may be installed over the opening to close the receiving chamber. The positive electrode, the negative electrode, and the separator may form an electrode assembly (52) through a winding process or a lamination process. The electrode assembly (52) is packaged within the receiving chamber. An electrolyte is infiltrated into the electrode assembly (52). The number of electrode assemblies (52) included in the sodium battery (5) may be one or more, and a person skilled in the art may select according to specific actual needs.

[0122] In some embodiments, the sodium battery may be assembled into a battery module, and the number of sodium batteries included in the battery module may be one or more, and the specific number may be selected by a person skilled in the art according to the application and capacity of the battery module.

[0123] FIG. 3 is a battery module (4) as an example. Referring to FIG. 3, a plurality of sodium batteries (5) in the battery module (4) may be installed by arranging them sequentially along the longitudinal direction of the battery module (4). Of course, they may also be arranged in any other arbitrary manner. Additionally, the plurality of sodium batteries (5) may be secured with fasteners.

[0124] Optionally, the battery module (4) may also include a housing having a receiving space, and a plurality of sodium batteries (5) are received in the receiving space.

[0125] In some embodiments, the battery module described above may also be assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, and the specific number may be selected by a person skilled in the art according to the application and capacity of the battery pack.

[0126] FIGS. 4 and FIGS. 5 are a battery pack (1) as an example. Referring to FIGS. 4 and FIGS. 5, the battery pack (1) may include a battery case and a plurality of battery modules (4) installed in the battery case. The battery case includes an upper case (2) and a lower case (3), the upper case (2) is installed over the lower case (3) and forms a closed space for accommodating the battery modules (4). The plurality of battery modules (4) may be arranged in any manner in the battery case.

[0127] In addition, the present application also provides an electric device, said electric device comprising at least one of a sodium battery, a battery module, or a battery pack provided in the present application. The sodium battery, battery module, or battery pack may be used as a power source for said electric device or as an energy storage unit for said electric device. The electric device may include, but is not limited to, 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.

[0128] As for the electrical device, a sodium battery, battery module, or battery pack can be selected depending on the usage demand.

[0129] FIG. 6 is an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the demand for high power and high energy density for the sodium battery of the electric device, a battery pack or battery module may be used.

[0130] Other examples of devices may include mobile phones, tablet computers, laptops, etc. Typically, such devices must be thin and light and capable of using sodium batteries as a power source.

[0131] Examples

[0132] The following describes embodiments of the present application. The embodiments described below are illustrative and are intended only to interpret the present application and should not be construed as a limitation thereof. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature of the art or product descriptions. Where the manufacturer of the reagents or equipment used is not specified, they are all general products available on the market.

[0133] A. Manufacturing method

[0134] Example 1:

[0135] 1) Manufacture of cathode

[0136] 5g of sodium carboxymethylcellulose (CMC-Na) was weighed, stirred, and dissolved in 1000mL of water, then 5g of single-walled carbon nanotubes were added and dispersed using ultrasound to prepare a slurry. The slurry was coated onto the surface of a copper foil cathode current collector, and a cathode piece was obtained after drying, slitting, and cutting.

[0137] 2) Manufacturing of the anode section

[0138] Sodium iron pyrophosphate, which is the positive active material, carbon nanotubes, which is the conductor, and polyvinylidene fluoride, which is the adhesive, are sufficiently stirred and mixed in an appropriate amount of N-methylpyrrolidone (NMP) in a mass ratio of 95:2:3 to uniformly form a positive slurry; the positive slurry is coated on the surface of an aluminum foil positive current collector, and after drying, cold pressing, and die cutting, a positive plate with a thickness of 200 μm is obtained.

[0139] 3) Preparation of electrolyte

[0140] In an argon atmosphere glove box (H2O content < 10 ppm, O2 content < 1 ppm), diethylene glycol dimethyl ether and tetrahydrofuran were mixed in a mass ratio of 1:3, sodium hexafluorophosphate (NaPF6) was added, and after uniform stirring, an electrolyte with a NaPF6 concentration of 1 mol / L was obtained.

[0141] 4) Separator

[0142] A 9 μm polyethylene (PE) porous polymer film was used as a separator.

[0143] 5) Manufacture of sodium batteries

[0144] The positive electrode, separator, and negative electrode manufactured in the above steps are sequentially stacked so that the separator is positioned between the positive electrode and the negative electrode and so that the positive electrode and the negative electrode can be separated; then, the stacked components described above are wound to obtain an electrode assembly;

[0145] The electrode assembly was installed in a rectangular housing, heat-press molding was performed, and a first helium leak test was performed. After the first helium leak test was completed, it was dried by baking, and the electrolyte prepared as described above was injected into the sodium battery housing. One hour after the liquid injection was completed, argon with a pressure of 50 kPa was injected into the housing and continuously injected for 5 seconds, and after being left standing for 24 hours, the sodium battery was charged at a constant current of 0.33 C at 45°C under an atmosphere containing an inert gas in the housing until the voltage reached 3.65 V, and then charged at a constant voltage until the current was less than 0.05 C, and formation was performed under an open atmospheric pressure state.

[0146] After the formation was completed, the battery underwent settling and molding, followed by a capacity test. The initial discharge capacity was obtained by performing a constant current discharge at a current of 0.33C until the voltage reached 1.5V. The housing was welded using sealing nails, and after undergoing processes such as a final helium leak test, the cathode-free sodium battery of Example 1 was obtained.

[0147] Examples 2~4

[0148] The manufacturing method of the sodium batteries in Examples 2 to 4 is substantially the same as the manufacturing method of Example 1, differing in that the type of inert gas injected is different. In Example 2, helium was injected, in Example 3, nitrogen was injected, and in Example 4, a mixed gas with a volume ratio of argon:helium:nitrogen of 1:1:1 was injected. Refer to Table 1 for specific parameters.

[0149] Example 5

[0150] The method of manufacturing the sodium battery of Example 5 is substantially the same as the method of manufacturing Example 1, differing in that the pressure of the injected argon is 25 kPa, and specific parameters are referenced in Table 1.

[0151] Example 6

[0152] The method of manufacturing the sodium battery of Example 6 is substantially the same as the method of manufacturing Example 1, differing in that the pressure of the injected argon is 100 kPa, and specific parameters are referenced in Table 1.

[0153] Example 7

[0154] The method of manufacturing the sodium battery of Example 7 is substantially the same as the method of manufacturing Example 1, except that the time for continuously injecting argon is 2 seconds, and specific parameters are referenced in Table 1.

[0155] Example 8

[0156] The method of manufacturing the sodium battery of Example 8 is substantially the same as the method of manufacturing Example 1, except that the time for continuously injecting argon is 15 seconds, and specific parameters are referenced in Table 1.

[0157] Example 9

[0158] The method of manufacturing the sodium battery of Example 9 is substantially the same as the method of manufacturing of Example 1, and the differences are as follows:

[0159] The prepared electrolyte was injected into the sodium battery housing, and 6 hours after the liquid injection was completed, argon with a pressure of 50 kPa was injected into the housing and continuously injected for 5 seconds, and after being left to stand for 12 hours, the sodium battery was phosphating under an atmosphere containing an inert gas in the gas inside the housing.

[0160] Example 10

[0161] The method of manufacturing the sodium battery of Example 10 is substantially the same as the method of manufacturing of Example 1, and the differences are as follows:

[0162] The prepared electrolyte was injected into the sodium battery housing, and 12 hours after the liquid injection was completed, argon with a pressure of 50 kPa was injected into the housing and continuously injected for 5 seconds, and after being left to stand for 12 hours, the sodium battery was phosphating under an atmosphere containing an inert gas in the gas inside the housing.

[0163] Example 11

[0164] The method of manufacturing the sodium battery of Example 11 is substantially the same as the method of manufacturing in Example 1, the difference being that Example 11 is a hard carbon cathode sodium battery, and the method of manufacturing the cathode is as follows:

[0165] Hard carbon as the cathode active material, carbon black as the conductor, and sodium carboxymethylcellulose as the adhesive were sufficiently stirred and uniformly mixed in a deionized water solvent system in a mass ratio of 90:5:5 to obtain a cathode slurry; the cathode slurry was uniformly coated onto a copper foil cathode current collector; the copper foil was dried at room temperature, then transferred to a 120°C oven and dried for 1 hour, and then a cathode piece was obtained through cold pressing and slitting.

[0166] Comparative Example 1

[0167] The method of manufacturing the sodium battery of Comparative Example 1 is substantially the same as the method of manufacturing Example 1, except that an inert gas is not injected into the sodium battery housing at the stage after the electrolyte injection is completed and before the sodium battery formation treatment begins, and specific parameters are indicated in Table 1.

[0168] Comparative Example 2

[0169] The manufacturing method of the sodium battery of Comparative Example 2 is substantially the same as the manufacturing method of Example 1, except that before the sodium battery is formed, vacuum suction is applied so that the air pressure inside the battery housing is -30 Kpa, and specific parameters are referenced in Table 1.

[0170] Comparative Example 3

[0171] The method of manufacturing the sodium battery of Comparative Example 3 is substantially the same as the method of manufacturing Example 11, except that an inert gas is not injected at the stage after the electrolyte injection is completed and before the sodium battery formation treatment begins, and specific parameters are shown in Table 2.

[0172] B. Battery Performance test

[0173] 1. Initial Coulomb Efficiency Test

[0174] In the manufacturing process of the sodium batteries of Examples 1 to 11 and Comparative Examples 1 to 3, a test of the initial Coulomb efficiency was performed, wherein the charge capacity at the completion of the phosphating treatment was set as the initial charge capacity C1, the discharge capacity at the time of the capacity test was set as the initial discharge capacity C2, and the initial Coulomb efficiency of the battery = C2 / C1 × 100%.

[0175] C. Each Examples , Comparative example Analysis of test results

[0176] Batteries of each example and comparative example were manufactured according to the method described above, and each performance parameter was measured, and the results are referenced in Tables 1 and 2.

[0177] number Sodium battery manufacturing process sodium battery Types of injected gas Injection point Injection pressure / kpa Injection time / second Presence or absence of cathode Battery housing Battery primary efficiency Argon volume ratio Helium volume ratio Nitrogen volume ratio Example 1 argon 1 hour after fluid infusion is complete 50 5 doesn't exist 30% 5% 0% 93% Example 2 helium 1 hour after fluid infusion is complete 50 5 doesn't exist 0% 30% 0% 92.8% Example 3 nitrogen 1 hour after fluid infusion is complete 50 5 doesn't exist 0% 5% 30% 92.9% Example 4 A mixed gas with a volume ratio of argon:helium:nitrogen of 1:1:1 1 hour after fluid infusion is complete 50 5 doesn't exist 10% 10% 10% 92.9% Example 5 argon 1 hour after fluid infusion is complete 25 5 doesn't exist 15% 5% 0% 92.5% Example 6 argon 1 hour after fluid infusion is complete 100 5 doesn't exist 40% 5% 0% 93.2% Example 7 argon 1 hour after fluid infusion is complete 50 2 doesn't exist 20% 5% 0% 92.7% Example 8 argon 1 hour after fluid infusion is complete 50 15 doesn't exist 45% 5% 0% 93.3% Example 9 argon 6 hours after completion of fluid infusion 50 5 doesn't exist 20% 5% 0% 92.6% Example 10 argon 12 hours after completion of fluid infusion 50 5 doesn't exist 10% 5% 0% 92.2% Comparative Example 1 / / / / doesn't exist 0% 5% 0% 88% Comparative Example 2 argon Inject 1 hour after liquid injection is complete, and vacuum suction to reduce the housing pressure to -30kPa before starting the phosphating process. 50 5 doesn't exist 5% 5% 0% 88.5%

[0178] number Sodium battery manufacturing process sodium battery Types of injected gas Injection point Injection pressure / kpa Injection time / second Presence or absence of cathode Battery housing Battery primary efficiency Argon volume ratio Helium volume ratio Nitrogen volume ratio Example 11 argon 1 hour after fluid infusion is complete 50 5 Hard carbon cathode 30% 5% 0% 85% Comparative Example 3 / / / / Hard carbon cathode 0% 5% 0% 83.5%

[0179] As can be seen from Examples 1 to 11, when an electrolyte is injected into a sodium battery, an inert gas is injected into the sodium battery housing, and the sodium battery is phosphating under an atmosphere containing the inert gas in the gas inside the sodium battery housing, the sodium battery has excellent initial Coulomb efficiency.

[0180] As can be seen from the comparison of Examples 1 to 10 with Comparative Examples 1 to 2, Example 11, and Comparative Example 3, when an electrolyte is injected into a sodium battery, an inert gas is injected into the sodium battery housing, and the sodium battery is phosphating under an atmosphere in which the gas inside the sodium battery housing contains the inert gas, it is advantageous to improve the primary efficiency of the sodium battery.

[0181] As can be seen from Examples 1 to 4, when a sodium battery is formed under an atmosphere in which an inert gas is included in the gas inside the sodium battery housing, and the inert gas includes one or more of argon, helium, and nitrogen, the sodium battery has excellent primary efficiency.

[0182] As can be seen from Examples 1, 5, and 6, when the pressure of the inert gas injected into the sodium battery housing is 25 kPa to 100 kPa, the sodium battery has excellent primary efficiency.

[0183] As can be seen from Examples 1, 7, and 8, when the time for injecting an inert gas into the sodium battery housing is 2 to 15 seconds, the sodium battery has excellent primary efficiency.

[0184] As can be seen from Examples 1 and 9, when an inert gas is injected 1 to 6 hours after the electrolyte injection into the sodium battery is completed, the sodium battery has excellent primary efficiency.

[0185] As can be seen from the comparison of Examples 1 and 9 and Example 10, injecting an inert gas 1 to 6 hours after the electrolyte injection into the sodium battery is completed is advantageous for improving the primary efficiency of the sodium battery.

[0186] It should be noted that the present application is not limited to the embodiments described above. The embodiments described above are merely examples, and any embodiments having substantially the same configuration as the technical concept and exhibiting the same functional effects within the scope of the technical solution of the present application are included within the technical scope of the present application. Furthermore, other methods constructed by applying various modifications to the embodiments conceived by a person skilled in the art without departing from the spirit of the present application, and by combining parts of the components of the embodiments, are also included within the scope of the present application. Explanation of the symbols

[0187] 1: Battery pack; 2: Top case; 3: Bottom case; 4: Battery module; 5: Sodium battery; 51: Housing body; 52: Electrode assembly; 53: Cover plate.

Claims

Claim 1 A sodium battery characterized in that, based on the total volume of gas within the sodium battery housing, the total volume ratio of the inert gas is 15% to 50%. Claim 2 A sodium battery according to claim 1, characterized in that the total volume ratio of the inert gas is 30% to 45% based on the total volume of the gas inside the sodium battery housing. Claim 3 A sodium battery according to claim 1 or 2, characterized in that the inert gas comprises one or more of argon, helium, and nitrogen. Claim 4 A sodium battery according to any one of claims 1 to 3, wherein the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, the positive film layer comprises a positive active material, and the positive active material comprises a polyanionic compound. Claim 5 A sodium battery according to claim 4, wherein the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr. Claim 6 A sodium battery according to claim 5, characterized in that the polyanionic compound comprises at least one of sodium iron phosphate pyrophosphate, sodium vanadium phosphate, and sodium iron pyrophosphate. Claim 7 A sodium battery according to any one of claims 1 to 6, characterized in that the sodium battery includes a sodium battery without a negative electrode and a sodium metal battery. Claim 8 A method for forming a sodium battery, comprising the steps of: injecting an electrolyte into a sodium battery housing; injecting an inert gas into a sodium battery housing; and performing a formation process on the sodium battery; wherein, the method is characterized by not including the step of performing vacuum suction on the sodium battery housing after the inert gas injection is completed and before the sodium battery formation process begins. Claim 9 A method for chemistry according to claim 8, wherein the inert gas comprises one or more of argon, helium, and nitrogen. Claim 10 A method for chemical conversion according to claim 8 or 9, wherein the pressure of the inert gas when injecting the inert gas is 25 kPa to 100 kPa; and / or, the injection time when injecting the inert gas is 2 seconds to 15 seconds. Claim 11 A method for chemical conversion characterized by injecting an inert gas 1 to 6 hours after the completion of the electrolyte injection in any one of claims 8 to 10. Claim 12 A method for forming a battery according to any one of claims 8 to 11, wherein the sodium battery comprises a positive plate, the positive plate comprises a positive current collector and a positive film layer installed on at least one side of the positive current collector, the positive film layer comprises a positive active material, and the positive active material comprises a polyanionic compound. Claim 13 A method of chemical conversion according to claim 12, wherein the polyanionic compound comprises one or more of Na3M2(PO4)3, Na2XP2O7, and a mixed polyanionic compound of phosphate and pyrophosphate, wherein M and X are each independently selected from one or more of Al, Ti, V, Fe, Cr, Mn, Co, Ni, Ca, Mg, Nb, and Zr. Claim 14 A method of chemical conversion according to claim 12 or 13, wherein the polyanionic compound comprises at least one of sodium iron phosphate pyrophosphate, sodium vanadium phosphate, and sodium iron phosphate. Claim 15 A method for forming a sodium battery according to any one of claims 8 to 14, characterized in that the sodium battery comprises a sodium battery without a negative electrode and a sodium metal battery. Claim 16 An electric device characterized by comprising a sodium battery according to any one of claims 1 to 7 or a sodium battery manufactured using a method of forming a sodium battery according to any one of claims 8 to 15.

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