Battery monomer and preparation method thereof, battery device, power utilization device and energy storage device

Abstract

The invention provides a battery monomer and a preparation method thereof, a battery device, a power utilization device and an energy storage device, the battery monomer comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte, the positive electrode comprises a positive electrode material, the positive electrode material comprises a transition metal element, the transition metal element comprises at least one of Mn, Ni and Co, and the electrolyte comprises at least one of Mn, Ni and Co. The electrolyte comprises an organic solvent and an additive, and the additive comprises a chemical general formula shown as a formula I: in the formula I, R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from any one of OH, CnH2n + 1, CnH2n + 1-mXm and SO3M, M is Li or Na, X is halogen, n is 1-10, and m is 0-(2n + 1); and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is selected from SO3M. (I).

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells and their preparation methods, battery devices, power consumption devices, and energy storage devices. Background Technology

[0002] In the field of energy storage cells, especially for the demand for high-energy-density batteries, traditional battery design faces significant technical challenges. With the rapid growth of the electric vehicle, large-scale energy storage system, and portable electronic device markets, higher requirements are being placed on battery energy density, cycle life, and safety performance.

[0003] However, while pursuing higher cycle life, current battery technology often encounters the dilemma of declining safety performance, which directly limits the efficiency of batteries in practical applications.

[0004] Therefore, how to effectively improve the cycle performance and safety performance of batteries remains one of the technical problems that need to be solved. Summary of the Invention

[0005] This application provides a battery cell and its preparation method, battery device, power consumption device and energy storage device. The battery cell of this application has high cycle life, excellent rate performance and safety performance, and improves the overall electrochemical performance of the battery cell.

[0006] In a first aspect, embodiments of this application provide a battery cell, comprising a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode comprises a positive electrode material, which includes a transition metal element, including at least one selected from Mn, Ni, and Co. The electrolyte comprises an organic solvent and an additive, the additive comprising a chemical formula as shown in Formula I: (I) In Formula I, R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are each independently selected from OH and C. n H 2n+1 C n H 2n+1-m X m The X is any one of SO3M, where M is Li or Na, X is a halogen, n = 1~10, m is 0~(2n+1), and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 is selected from SO3M.

[0007] Secondly, embodiments of this application provide a method for preparing a single battery cell, comprising the following steps: Diethylenetriaminepentanephosphonic acid was dehydrated to obtain the first precursor. The first precursor is subjected to a substitution reaction with a hydrophobic compound to obtain a second precursor, wherein the hydrophobic compound includes at least one of alkyl and halogen-substituted alkyl groups. The second precursor and a halogen-substituted sulfonic acid compound are reacted, followed by crystallization to obtain the additive. The additive and organic solvent are mixed to obtain an electrolyte; A positive electrode, a negative electrode, and a separator are provided. The positive electrode includes a positive electrode material, which includes a transition metal element, including at least one of Mn, Ni, and Co. The positive electrode, the negative electrode, and the separator are wound or stacked to obtain a battery cell assembly. The battery cell assembly and the housing are assembled to obtain a battery module; The electrolyte is injected into the battery module to obtain a single battery cell.

[0008] Thirdly, embodiments of this application provide a battery device, including a battery cell as described in the first aspect or a battery cell formed by a method for preparing a battery cell as described in the second aspect, the battery device including one or more of a battery module, a battery pack, and an energy storage battery.

[0009] Fourthly, embodiments of this application provide an electrical device, including a battery device as described in the third aspect, the battery device being used to provide electrical energy.

[0010] Fifthly, embodiments of this application provide an energy storage device, including a battery device as described in the third aspect, the battery device being used to store electrical energy.

[0011] The technical solution of this application has at least the following beneficial effects: The electrolyte of this application comprises an organic solvent and an additive as described in Formula I. In the skeleton of this additive, the oxygen atom in the phosphonate group, the nitrogen atom in the amine group, and the OH groups involved in R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 all provide lone pair electrons. The free transition metal ions (such as Mn) formed by the dissociation of the cathode material... 2+ Ni 2+ Co 2+The additive provides empty orbitals, and the multiple lone pairs of electrons contained in this application can form coordination bonds with the empty orbitals, enabling the electrolyte to actively adsorb transition metal ions, reducing the dissolution of transition metal ions and their migration to the negative electrode, thereby effectively suppressing the negative electrode interface failure problem caused by the dissolution of transition metal ions during battery cycling. Furthermore, the additive can coordinate with transition metal ions to generate a large coordination field splitting energy, which can change the d orbital arrangement of transition metal ions, preventing the formation of stable coordination activation intermediates between transition metal ions and reactants in negative electrode side reactions, suppressing the catalytic ability of transition metal ions for negative electrode side reactions, thus helping to suppress the occurrence of side reactions and improve the cycle performance of the battery cell. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is selected from SO3M, where M is Li or Na. SO3M is a lithium-philic group and can serve as an additional lithium-ion transport site, effectively compensating for the change in electrolyte viscosity caused by the addition of the additive, thereby maintaining the high ionic conductivity of the electrolyte. The battery cell of this application, by adding additives to the electrolyte, can suppress the catalytic ability of transition metal ions on the negative electrode side reaction and control the viscosity of the electrolyte, thereby achieving high cycle life, excellent rate performance and high temperature safety of the battery cell. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the preparation process of a battery cell provided in an embodiment of this application. Detailed Implementation

[0013] The following examples illustrate this solution. These examples are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0014] With the increasing penetration of intermittent renewable energy sources such as wind and solar power into the power grid, long-duration energy storage technology has become crucial for ensuring grid stability and enabling energy regulation across time periods. Storage durations of 4 to 8 hours or even longer can effectively achieve energy regulation across time periods (such as shifting midday photovoltaic power generation to nighttime peak electricity consumption), which is of great significance for ensuring grid security and improving energy efficiency.

[0015] As the basic building block of energy storage systems, energy storage cells can convert electrical energy into chemical energy, enabling energy storage and release. In the field of electrochemical cells, lithium-ion batteries, with their high energy density and high application potential, have become dominant in portable electronic devices, electric vehicles, and distributed energy storage systems. Their high energy density allows them to provide longer driving time within a limited size and weight, meeting the urgent needs of modern mobile devices and new energy vehicles for lightweight design and extended driving range. At the same time, lithium-ion batteries have mature material systems, advanced manufacturing processes, long cycle life, good fast-charging capabilities, and low self-discharge rates, making them a promising candidate for large-scale energy storage, smart grids, and renewable energy integration.

[0016] Furthermore, under the typical 8-hour long-term energy storage conditions of energy storage systems, lithium-ion batteries exhibit excellent electrochemical stability and high conversion efficiency, precisely adapting to long-term charge-discharge requirements. Their positive and negative electrode materials possess regular crystal structures and stable lithium insertion / extraction mechanisms, suppressing material structure distortion and irreversible loss of active materials during prolonged high-charge-state resting and slow charge-discharge processes, maintaining high capacity retention and coulombic efficiency. Simultaneously, the electrolyte and electrode interfaces exhibit good compatibility, with a gradual increase in interface impedance. The stable SEI film effectively suppresses side reactions such as electrolyte decomposition and lithium dendrite growth. Combined with efficient and reversible charge transfer reactions, it avoids intensified polarization and electrode damage, achieving highly efficient and controllable energy storage and release in long-term energy storage scenarios.

[0017] Despite the high energy density and application potential of lithium-ion batteries, they still face significant challenges on the road to large-scale energy storage applications. One major obstacle hindering their development is the dissolution of transition metal ions from the cathode material, leading to decreased cycle life and safety performance. Specifically, cathode materials containing transition metals are prone to lattice oxygen loss under long cycles or high voltages, resulting in the dissolution of these transition metals. These dissolved transition metal ions possess strong catalytic activity, catalyzing the decomposition of the electrolyte at the anode interface. This leads to an increase in decomposition products and interfacial impedance. The high-impedance anode interface easily induces the formation of lithium dendrites, which not only consumes active lithium ions but may also cause internal short circuits, further deteriorating the cycle performance and safety of lithium-ion batteries.

[0018] Therefore, embodiments of this application provide a battery cell, including a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode includes a positive electrode material, which includes a transition metal element, including at least one selected from Mn, Ni, and Co. The electrolyte includes an organic solvent and an additive, the additive comprising a chemical formula as shown in Formula I: Ⅰ In Formula I, R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are each independently selected from OH and C. n H 2n+1 C n H 2n+1-m X m The X is any one of SO3M, where M is Li or Na, X is a halogen, n = 1~10, m is 0~(2n+1), and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 is selected from SO3M.

[0019] In the above scheme, the electrolyte of this application includes an organic solvent and the additive described in Formula I. In the skeleton of the additive, the oxygen atom in the phosphonate group, the nitrogen atom in the amine group, and the OH groups involved in R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 all provide lone pair electrons. The free transition metal ions (such as Mn) formed by the dissociation of the cathode material... 2+ Ni 2+ Co 2+ The additive provides empty orbitals, and the multiple lone pairs of electrons contained in this application can form coordination bonds with the empty orbitals, enabling the electrolyte to actively adsorb transition metal ions, reducing the dissolution of transition metal ions and their migration to the negative electrode, thereby effectively suppressing the negative electrode interface failure problem caused by the dissolution of transition metal ions during battery cycling. Furthermore, the additive can coordinate with transition metal ions to generate a large coordination field splitting energy, which can change the d orbital arrangement of transition metal ions, preventing the formation of stable coordination activation intermediates between transition metal ions and reactants in negative electrode side reactions, suppressing the catalytic ability of transition metal ions for negative electrode side reactions, thus helping to suppress the occurrence of side reactions and improve the cycle performance of the battery cell. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is selected from SO3M, where M is Li or Na. SO3M is a lithium-philic group and can serve as an additional lithium-ion transport site, effectively compensating for the change in electrolyte viscosity caused by the addition of the additive, thereby maintaining the high ionic conductivity of the electrolyte. The battery cell of this application, by adding additives to the electrolyte, can suppress the catalytic ability of transition metal ions on the negative electrode side reaction and control the viscosity of the electrolyte, thereby achieving high cycle life, excellent rate performance and high temperature safety of the battery cell.

[0020] Furthermore, the additives described in Formula I are effective against protons (H). +It has strong binding force and can directly capture free HF in the electrolyte, significantly reduce the acidity of the electrolyte system, improve the cleanliness of the electrolyte, alleviate the corrosion of the positive electrode material and the dissolution of transition metals, and promote the formation of a thinner, denser and more stable SEI film on the negative electrode, which significantly reduces the loss of active lithium and the increase of interface impedance during cycling.

[0021] In related technologies, the transition metal element in the cathode material includes at least one of Mn, Ni, and Co. For example, Mn 2+ The five d electrons occupy all five orbitals, all of which are unpaired, exhibiting extremely high catalytic activity. They can efficiently catalyze the decomposition of the electrolyte on the negative electrode surface, generating a large number of byproducts, consuming active lithium, and leading to battery performance degradation. The additive in this application can form coordinate bonds with transition metal elements in the positive electrode material. These coordinate bonds, through the coordination field effect, generate a huge coordination field splitting energy that forces the d electrons of the transition metal ions to rearrange from a high-spin state to a low-spin state. This reduces the number of unpaired electrons in the transition metal ions, significantly decreasing their catalytic activity against side reactions and fundamentally reducing the catalytic activity of the transition metal elements.

[0022] In some implementations, R1 and R2 are each independently selected from C. n H 2n+1-m X m And any of SO3M, where X is a halogen, C n H 2n+1-m X m As a hydrophobic group, this application uses the above-mentioned hydrophobic group C n H 2n+1-m X m The presence of the lithium-loving group SO3M in the middle position of the additive described in Formula I not only enhances the chemical stability of the additive and ensures its activity, but also allows the hydrophobic group to prevent the coordinated transition metal element from approaching the positive / negative electrode interface through steric hindrance. In other words, the hydrophobic group can accumulate at the positive / negative electrode interface to form a dynamic barrier, blocking the penetration of water molecules, further inhibiting the occurrence of side reactions in the electrolyte, and improving the capacity retention, rate performance, and safety performance of the battery cell.

[0023] In some embodiments, R1 is C n H 2n+1-m X m R2 is SO3M. In other embodiments, R1 is SO3M and R2 is C. n H 2n+1-m X m .

[0024] In some implementations, R1 is selected from SO3Li and C8F. 17 R2 is selected from SO3Li and C8F.17 Any one of the following, and R1 and R2 are different. SO3Li, as a lithiophilic group, effectively improves the ionic conductivity of the electrolyte. Simultaneously, SO3Li dissociates to form ion channels, effectively reducing the viscosity of the electrolyte system and minimizing the impact of additives on the electrolyte system viscosity. C8F 17 Perfluorooctyl is a perfluorooctyl group in which all hydrogen atoms in the octyl group are replaced by fluorine, forming a saturated perfluoroalkyl chain, exhibiting excellent hydrophobic properties and chemical stability. This application uses SO3Li and C8F... 17 Positioning it in the middle of the additive skeleton not only enhances the chemical stability of the additive but also effectively utilizes SO3Li and C8F. 17 Lithophilicity and steric hindrance effects.

[0025] In some embodiments, R1 is C8F 17 R2 is SO3Li. In other embodiments, R1 is SO3Li and R2 is C8F. 17 .

[0026] In some embodiments, R3, R4, R5, R6, R7, R8, R9 and R10 are all OH, which can provide lone pairs of electrons for the additive, which is beneficial for the additive to form coordination bonds with transition metal ions, thereby improving the adsorption capacity of the electrolyte for transition metal ions and reducing the dissolution of transition metal ions.

[0027] In some embodiments, the additive content in the electrolyte is 1wt% to 2wt%. Specifically, the additive content in the electrolyte can be 1wt%, 1.3wt%, 1.5wt%, 1.8wt%, 2wt%, or any two of the above values. Controlling the additive content in the electrolyte within this range helps to suppress the dissolution of transition metal ions and the side reactions of the positive / negative electrodes, while not excessively affecting the viscosity of the electrolyte. This helps to maintain a balance between suppressing the dissolution of transition metal ions and ensuring viscosity, thereby giving the battery cell advantages such as high cycle life, high ionic conductivity, and good safety performance. If the additive content in the electrolyte is less than 1wt%, the electrolyte's suppression of the dissolution of transition metal ions and the suppression of the side reactions of the positive / negative electrodes are poor, the performance improvement of the battery cell is not significant, and the improvement in the cycle life and stability of the battery cell is not significant. If the additive content in the electrolyte exceeds 2 wt%, it will lead to an excessive increase in electrolyte viscosity, excessively high interfacial impedance, reduced lithium-ion transport efficiency, decreased rate performance of battery cells, accelerated capacity decay, and increased safety risks.

[0028] In some embodiments, the additive has a crystal structure with a periodic and ordered arrangement. The additive of this application has a crystal structure, which can effectively improve the distribution stability and electrochemical stability when added to the electrolyte.

[0029] In some embodiments, the volumetric particle size distribution D of the additive 10 The particle size distribution of the additive is 3μm~8μm, specifically, the volumetric particle size distribution D. 10 It can be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, or any two of the above values ​​within the range. D 10 The particle size of the additive particles represents the volume percentage content reaching 10% on the cumulative curve, that is, D. 10 This refers to the particle size at which the cumulative number (or mass) of additive particles reaches 10% of the total number (or mass) after sorting the additive particles according to their particle size.

[0030] In some embodiments, the volumetric particle size distribution D of the additive 50 The particle size distribution of the additive is 18μm~28μm; specifically, the volumetric particle size distribution D... 50 It can be 18μm, 20μm, 22μm, 24μm, 26μm, 28μm, or any two of the above values ​​within the range. D 50 This represents the particle size of the additive particles when the volume percentage on the cumulative curve reaches 50%.

[0031] In some embodiments, the volumetric particle size distribution D of the additive 90 The particle size distribution of the additive is 45μm~70μm, specifically, the volumetric particle size distribution D. 90 It can be 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, or any two of the above values ​​within the range. D 90 This represents the particle size of the additive particles when the volume percentage on the cumulative curve reaches 90%.

[0032] This application controls the volume particle size distribution D of the additive. 10 D 50 and D 90 Within the aforementioned range, the additive exhibits high dispersion stability and is not prone to aggregation and sedimentation. Furthermore, the size of the additive is well-matched with the pore size of the positive / negative electrode (generally within 70 μm), making it less likely to block ion transport channels and thus contributing to improved stability and long-lasting functionality of the additive.

[0033] In some implementations, each additive can capture 2-5 transition metal ions during the charge and discharge process of a single battery cell. This capture of 2-5 transition metal ions during the charge and discharge process of a single battery cell enables the adsorption of most of the transition metal ions dissolved in the positive electrode. Simultaneously, it forms a dynamic barrier at the positive / negative electrode interface, suppressing the catalytic ability of transition metal ions on negative electrode side reactions and inhibiting the occurrence of side reactions.

[0034] In some embodiments, the conductivity of the electrolyte is 10 mS / cm to 11 mS / cm, specifically 10 mS / cm, 10.1 mS / cm, 10.3 mS / cm, 10.5 mS / cm, 10.7 mS / cm, 11 mS / cm, or any two of the above values. The electrolyte of this application has high conductivity, which reduces lithium-ion transport efficiency and improves the rate performance and cycle stability of the battery cells.

[0035] In some embodiments, the mass content of free hydrofluoric acid in the electrolyte is 2ppm to 10ppm, specifically 2ppm, 3ppm, 4ppm, 5ppm, 6ppm, 7ppm, 8ppm, 9ppm, 10ppm or any two of the above values.

[0036] In some embodiments, the water content in the electrolyte is 3 ppm to 6 ppm by mass, specifically 3 ppm, 4 ppm, 5 ppm, 6 ppm or any two of the above values.

[0037] The main products of electrolyte hydrolysis are hydrofluoric acid, water, and metal hydroxides. The presence of hydrofluoric acid corrodes the transition metal ions at the positive electrode, causing them to dissolve and migrate to the negative electrode. There, they react with the active lithium at the negative electrode to form lithium metal compounds, resulting in irreversible loss of active lithium. The presence of water damages the SEI film at the negative electrode, causing repeated rupture and repair, continuously consuming active lithium. This application controls the mass content of free hydrofluoric acid and water in the electrolyte within the aforementioned ranges, indicating that the electrolyte is in a low-moisture and low-hydrofluoric acid environment. This greatly alleviates the corrosion of the positive electrode material and the dissolution of transition metal ions, improves the cleanliness of the electrolyte, and promotes the formation of a thinner, denser, and more stable SEI film at the negative electrode, significantly reducing active lithium loss and interfacial impedance growth during battery cell cycling.

[0038] In some embodiments, the cathode material includes at least one of high-nickel ternary cathode material, transition metal oxide cathode material, olivine-type cathode material, and sodium transition metal oxide cathode material.

[0039] In some embodiments, the cathode material includes at least one of lithium nickel cobalt manganese oxide cathode material, lithium nickel cobalt aluminum oxide cathode material, lithium cobalt oxide cathode material, lithium manganese iron phosphate cathode material, sodium manganese iron copper oxide cathode material, and sodium nickel iron manganese oxide cathode material.

[0040] The above-mentioned cathode materials all contain at least one transition metal element selected from Mn, Ni, and Co. When the above-mentioned cathode materials and the electrolyte containing additives and organic solvents of this application are used together as a battery cell, the electrolyte can effectively adsorb transition metal ions, effectively suppress the negative electrode interface failure problem caused by the dissolution of transition metal ions, and at the same time suppress the catalytic ability of transition metal ions on negative electrode side reactions, which is beneficial to suppressing the occurrence of side reactions and improving the safety performance and cycle performance of the battery cell.

[0041] In some embodiments, the organic solvent includes at least one selected from ethylene carbonate, fluoroethylene carbonate, dimethyl carbonate, propylene carbonate, chain carbonates, and carboxylic acid esters. These organic solvents possess good wettability, allowing them to fully wet the pores of the electrode material and the microporous structure of the separator, ensuring the wetting of the electrode-electrolyte and separator-electrolyte interfaces. This ensures the continuity of lithium-ion conduction throughout the battery system and avoids increased internal resistance due to poor interfacial contact.

[0042] In some embodiments, the electrolyte further includes an electrolyte salt, which includes at least one of lithium salt, sodium salt, potassium salt, and magnesium salt. This application adds the aforementioned electrolyte salt to the electrolyte, which serves as the primary source of lithium ions, thereby improving the ionic conductivity of the electrolyte and enhancing the rate performance and low-temperature cycling performance of the battery cells.

[0043] In some embodiments, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The sodium salt includes at least one selected from sodium hexafluorophosphate (NaPF6) and sodium bis(trifluoromethanesulfonyl)imide (NaTFSI). The potassium salt includes at least one selected from potassium hexafluorophosphate (KPF6) and potassium bis(trifluoromethanesulfonyl)imide (KTFSI). The magnesium salt includes at least one selected from magnesium perchlorate (Mg(ClO4)2) and magnesium bis(trifluoromethanesulfonyl)imide Mg(TFSI)2.

[0044] Taking electrolyte salts including LiPF6 as an example, LiPF6 is particularly sensitive to water. LiPF6 readily undergoes hydrolysis with water to produce hydrofluoric acid, lithium fluoride, etc. Hydrofluoric acid corrodes the transition metal ions in the positive electrode material, causing them to dissolve and migrate to the negative electrode. There, they react with the active lithium in the negative electrode to form lithium metal compounds, resulting in irreversible loss of active lithium. Lithium fluoride is an insoluble solid and hinders lithium-ion transport. The C in the additive of this application... n H 2n+1 Cn H 2n+1-m X m The group is a hydrophobic chain, which can suppress the hydrolysis side reaction of LiPF6, reduce the consumption of active lithium, and improve the capacity retention of battery cells.

[0045] This application also provides a method for preparing the above-mentioned battery cell. Figure 1 This is a schematic diagram of the preparation process for the battery cell of this application, as shown below. Figure 1 As shown, it includes the following steps: Diethylenetriaminepentanephosphonic acid was dehydrated to obtain the first precursor. The first precursor is subjected to a substitution reaction with a hydrophobic compound to obtain a second precursor, wherein the hydrophobic compound includes at least one of alkyl and halogen-substituted alkyl groups. The second precursor and a halogen-substituted sulfonic acid compound are reacted, followed by crystallization to obtain the additive. The additives and organic solvents are mixed to obtain the electrolyte; A positive electrode, a negative electrode, and a separator are provided. The positive electrode includes a positive electrode material, which includes a transition metal element, including at least one of Mn, Ni, and Co. The positive electrode, the negative electrode, and the separator are wound or stacked to obtain a battery cell assembly. The battery cell assembly and the casing are assembled to obtain a battery module; Electrolyte is injected into the battery module to obtain a single battery cell.

[0046] In the above technical solution, this application uses a first precursor obtained by dehydrating diethylenetriaminepentamethylenephosphonic acid as the basic framework of the additive. The first precursor first undergoes a substitution reaction with a hydrophobic compound, then reacts with a halogen-substituted sulfonic acid compound, and finally undergoes crystallization treatment to prepare the additive shown in formula (I). The additive of this application and a positive electrode, a negative electrode, an electrolyte, and a separator containing at least one transition metal element including Mn, Ni, and Co are used to make a battery cell. The presence of the additive can inhibit the dissolution of transition metal ions in the positive electrode material, inhibit the catalytic ability of transition metal ions on the negative electrode side reaction, and improve the cleanliness of the electrolyte, thereby achieving high cycle life, excellent rate performance, and high-temperature safety of the battery cell.

[0047] The preparation method of the battery cell of this application is described in detail below.

[0048] A. Preparation of additives.

[0049] S100. Diethylenetriaminepentimidephosphonic acid is dehydrated to obtain the first precursor.

[0050] The specific steps include: adding diethylenetriaminepentamethylenephosphonic acid (DTPMP) powder and anhydrous THF (tetrahydrofuran) solvent to a high-pressure reactor, heating to 40℃~60℃ under stirring, and then bubbling with dry nitrogen (N2) for 22h~24h to remove moisture. During this process, the moisture content must be monitored in real time to ensure it is less than or equal to 15ppm, minimizing the adverse effects of moisture on the subsequently assembled battery cells.

[0051] The chemical structural formula of diethylenetriaminepentimidephosphonic acid (DTPMP) is shown in Formula II: (II) In some embodiments, the stirring speed is 100 rpm to 200 rpm, specifically 100 rpm, 130 rpm, 150 rpm, 180 rpm, 200 rpm, or any two of the above values.

[0052] S200. The first precursor is subjected to a substitution reaction with a hydrophobic compound to obtain the second precursor.

[0053] S201. Replace the reactor with N2 three times, add a hydrophobic compound, and carry out a reflux reaction under closed conditions to ensure that the residual mass content of DTPMP is less than or equal to 0.5%.

[0054] In some embodiments, the hydrophobic compound includes C n H 2n+2 C n H 2n+2-m X m At least one of the following. Wherein, X is a halogen, n = 1~10, and m is 0~(2n+1). Exemplary examples of hydrophobic compounds include C3H7, C3H7I, C4H9, C4H9I, and C5H... 11 C5H 11 I, C6H 13 C6H 13 I, C7H 15 C7H 15 I, C8H 17 C8H 17 I etc.

[0055] In some embodiments, the molar ratio of diethylenetriaminepentamethylenephosphonic acid to the hydrophobic compound is 1:(1~3), specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3, or any two of the above values. Controlling the molar ratio of diethylenetriaminepentamethylenephosphonic acid to the hydrophobic compound within the above range is used to design the substitution amount of the hydrophobic compound.

[0056] In some embodiments, the reflux reaction temperature is 70°C to 90°C, specifically 70°C, 73°C, 75°C, 78°C, 80°C, 83°C, 85°C, 88°C, 90°C, or any two of the above values.

[0057] In some embodiments, the hydrophobic compound includes at least one of alkyl and halogen-substituted alkyl groups.

[0058] In some embodiments, a hydrophobic compound is added under stirring conditions at a stirring rate of 200 rpm to 300 rpm, specifically 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, or 300 rpm. In some embodiments, the reflux reaction time is 10 h to 12 h, specifically 10 h, 10.5 h, 11 h, 11.5 h, 12 h, or any two of the above values.

[0059] S202. The material obtained in S201 is transferred to a rotary evaporator for concentration, and the THF solvent is recovered to obtain the second precursor.

[0060] In some embodiments, concentration is carried out in a water bath at 40°C to 60°C, and the vacuum degree of concentration is less than or equal to 0.1 kPa.

[0061] S300: The second precursor and the halogen-substituted sulfonic acid compound are reacted and then crystallized to obtain the additive.

[0062] S301. Dissolve the second precursor in anhydrous THF and then transfer it to a glass-jacketed reactor. Use a constant-pressure funnel to carry out a substitution reaction of the sulfonic acid compound. Test the pH of the substituted reaction product with pH paper to ensure that there is no free acid residue.

[0063] In some embodiments, the sulfonic acid compound includes at least one of chlorosulfonic acid, concentrated sulfuric acid, and methanesulfonic acid.

[0064] In some embodiments, the mass ratio of diethylenetriaminepentamethylenephosphonic acid to the sulfonic acid compound is (3~8):1, specifically 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, or any two of the above values. By controlling the mass ratio of diethylenetriaminepentamethylenephosphonic acid to the sulfonic acid compound within the above range, the number of sulfonic acid groups substituted on the diethylenetriaminepentamethylenephosphonic acid is designed.

[0065] In some embodiments, the substitution reaction temperature is 0°C to 30°C, specifically within the range of 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, or any two of the above values. By controlling the temperature of the substitution reaction, the substitution position of the halogen-substituted sulfonic acid compound is controlled. In some embodiments, the substitution reaction temperature is 0°C to 5°C, and the halogen-substituted sulfonic acid compound primarily substitutes the hydroxyl group on the central P-group of DTPMP. In some embodiments, the substitution reaction temperature is 10°C to 30°C, and the halogen-substituted sulfonic acid compound primarily substitutes the hydroxyl group on the peripheral P-group of DTPMP.

[0066] In some embodiments, the substitution reaction is carried out under stirring conditions, with a stirring speed of 300 rpm to 500 rpm, specifically 300 rpm, 350 rpm, 400 rpm, 450 rpm, 480 rpm, 500 rpm, or any two of the above values.

[0067] In some implementations, the substitution reaction takes 4 to 6 hours.

[0068] S302. The reaction solution obtained in S301 is poured into pre-cooled deionized water for quenching, extracted with diethyl ether, and the aqueous phase is collected.

[0069] S303. Transfer the aqueous phase to the crystallization vessel, slowly add lithium-containing compound powder or sodium-containing compound powder under stirring conditions, and then add an alcohol solvent to carry out the reaction.

[0070] In some embodiments, the lithium-containing compound may be, for example, LiOH, and the sodium-containing compound may be, for example, NaOH.

[0071] In some embodiments, the reaction temperature is 15°C to 25°C, and the pH of the reaction is 6.5 to 7.5.

[0072] S304. The material obtained in S303 is cooled and crystallized. The crystallized material is collected using a vacuum filter, and the filter cake is washed multiple times with pre-cooled ether. The filter cake is then transferred to a spray dryer for drying until the moisture content is below 10 ppm. Finally, the dried material is sieved and then vacuum-sealed into an aluminum-plastic composite bag in a vacuum glove box for storage.

[0073] In some implementations, the cooling crystallization temperature is -25°C to -15°C, and the cooling crystallization time is 3 to 4 hours.

[0074] In some implementations, the spray dryer is configured with the following parameters: inlet air temperature of 100°C to 120°C, outlet air temperature of 55°C to 65°C, atomization pressure of 0.6 MPa to 0.8 MPa, and nitrogen flow rate of 10 m / s². 3 / h~20 m3 / h.

[0075] It should be noted that this application does not limit the order of S200 and S300, and can make adaptive adjustments according to the actual preparation process and product structure.

[0076] B. Preparation of battery cells.

[0077] S400. The additives prepared above are mixed with organic solvents to obtain an electrolyte.

[0078] In some embodiments, the organic solvent includes at least one of ethylene carbonate, fluoroethylene carbonate, dimethyl carbonate, propylene carbonate, chain carbonate, and carboxylic acid ester.

[0079] In some embodiments, the additive content in the electrolyte is 1wt% to 2wt%.

[0080] S500 provides a positive electrode, a negative electrode, and a separator. The positive electrode includes a positive electrode material, which includes a transition metal element, including at least one of Mn, Ni, and Co. The positive electrode, negative electrode, and separator are wound or stacked to obtain a battery cell assembly.

[0081] In some embodiments, the positive electrode includes a positive electrode sheet, the positive electrode sheet includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode material.

[0082] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, lithium foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0083] In some embodiments, the cathode material includes at least one of high-nickel ternary cathode materials, transition metal oxide cathode materials, olivine-type cathode materials, and sodium transition metal oxide cathode materials. Optionally, the cathode material includes at least one of lithium nickel cobalt manganese oxide cathode materials, lithium nickel cobalt aluminum oxide cathode materials, lithium cobalt oxide cathode materials, lithium manganese iron phosphate cathode materials, sodium manganese iron copper oxide cathode materials, and sodium nickel iron manganese oxide cathode materials.

[0084] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0085] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0086] In some embodiments, the positive electrode can be prepared by dispersing the above-mentioned components for preparing the positive electrode, such as the positive electrode material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode after drying, cold pressing and other processes.

[0087] In some embodiments, the negative electrode includes a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode material.

[0088] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0089] In some embodiments, the negative electrode material may be a negative electrode material known in the art for use in battery cells. As an example, the negative electrode material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0090] In some embodiments, the negative electrode film layer may optionally include a binder. The binder may be selected from at least one of styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan.

[0091] In some embodiments, the negative electrode film may optionally include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0092] In some embodiments, the negative electrode film layer may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose).

[0093] In some embodiments, the negative electrode can be prepared by dispersing the components used to prepare the negative electrode, such as the negative electrode material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode after drying, cold pressing and other processes.

[0094] In some embodiments, the separator includes polyolefin separators, nonwoven separators, cellulose separators, and composite separators. Polyolefin separators may be, for example, at least one of polyethylene separators and polypropylene separators. Cellulose separators may be, for example, paper separators, and composite separators may be, for example, polypropylene / polyethylene / polypropylene composite separators.

[0095] This application assembles the above-mentioned positive electrode, negative electrode and separator using winding technology or stacking technology to obtain a battery cell assembly.

[0096] S600: Assemble the cell assembly and the casing to obtain a battery module.

[0097] S700: Inject the electrolyte prepared in S400 into the battery module to obtain a single battery cell.

[0098] This application provides a battery device including the aforementioned battery cell. This battery device can be used, but is not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft. A power system for an electrical device or energy storage device can be formed using the battery device disclosed in this application, improving battery performance, battery life, and safety.

[0099] This application provides an electrical device that uses a battery as a power source. The electrical device includes, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0100] The embodiments of this application will be further described below with reference to several examples. However, the embodiments of this application are not limited to the specific embodiments described below. Appropriate modifications can be made within the scope of the main claims.

[0101] Example 1 (1) Pretreatment of DTPMP (diethylenetriaminepentamethylenephosphonic acid) DTPMP (diethylenetriamine pentamethylphosphonic acid) powder and anhydrous THF solvent were added to a high-pressure reactor. The mixture was heated to 50°C with a stirring speed of 150 rpm and then bubbled through dry nitrogen (N2) for 23 hours. During this process, the moisture content must be monitored in real time to ensure that the system H2O ≤ 15 ppm.

[0102] (2) Substitution reaction a. Substitution reaction: The reactor loaded with pretreated DTPMP was purged with N2 three times, and C8F was added. 17 Liquid I was heated to 80°C under sealed conditions, with the stirring rate increased to 250 rpm, and refluxed for 12 hours to ensure that the residual DTPMP content was ≤0.5%. DTPMP and C8F 17 The molar ratio of I is 1:1.

[0103] b. Post-processing: The reaction solution obtained from the substitution reaction was transferred to a rotary evaporator and concentrated in a water bath at 450°C under a vacuum of ≤0.1 kPa. The THF solvent was recovered to obtain the intermediate DTPMP-C8F. 17 DTPMP-C8F 17 It is a viscous yellow liquid.

[0104] (3) Sulfonation and neutralization reactions a. Preprocessing: DTPMP-C8F 17 Dissolve in 15L of anhydrous THF and transfer to a glass-jacketed reactor with a low-temperature circulation tank to cool the temperature inside the glass-jacketed reactor to 3℃~5℃.

[0105] b. Sulfonation reaction: Under stirring speed of 500 rpm, ClSO3H was slowly added through a constant pressure dropping funnel, the temperature was maintained at 3℃~5℃ and the reaction was carried out for 5 hours. The absence of free acid was confirmed by pH test paper (pH≥4). The mass ratio of DTPMP to ClSO3H was 5:1.

[0106] c. Quenching and purification: The sulfonation reaction solution is quenched in pre-cooled deionized water, extracted with diethyl ether, and the aqueous phase is collected.

[0107] d. Neutralization reaction: Transfer the aqueous phase into the crystallization vessel, and slowly add LiOH powder and anhydrous ethanol while stirring, control the temperature at 20℃, and adjust the pH to about 7.

[0108] e. Cool the neutralization reaction solution to -20℃, age for 4 hours and induce crystallization. Collect the white solid using a vacuum filter, and wash the filter cake multiple times with pre-cooled ether. Transfer the wet filter cake to a spray dryer and set the parameters as follows: inlet air temperature 120℃, outlet air temperature 65℃, atomization pressure 0.8MPa, and nitrogen flow rate 10m / s. 3 / h, dry until the moisture content is below 10ppm, then pass the dried material through a 200-mesh sieve to obtain a white microcrystalline powder, which is the additive. Subsequently, the additive is vacuum-sealed into an aluminum-plastic composite bag in a vacuum glove box for storage.

[0109] The chemical structural formula of the additive is shown in Formula III: (III) (4) Preparation of electrolyte In a vacuum glove box, the organic solvents ethylene carbonate EC, fluoroethylene carbonate EMC, and dimethyl carbonate DMC were mixed in a volume ratio of 3:5:2. Then, an appropriate amount of LiPF6 was added to make the concentration of LiPF6 1.2 mol / L. Fluoroethylene carbonate and the additives obtained in step (4) were then added. The mixture was aged at 40°C for 2 hours and then filtered through a 0.2 μm filter membrane to remove impurities to obtain the electrolyte. The mass content of the additives in the electrolyte was 1.5 wt%, and the mass content of fluoroethylene carbonate in the electrolyte was 2 wt%.

[0110] (5) Assembly of battery cells LiNi cathode material 0.8 Co 0.1 Mn 0.1 O2, conductive carbon black, and binder polyvinylidene fluoride are mixed in a mass ratio of 93:5:2. Using NMP (N-methylpyrrolidone) as a solvent, the mixture is adjusted to a uniform slurry with a solid content of 58%. The slurry is uniformly coated onto aluminum foil, dried in an oven at 85°C, and then rolled. After slitting and die-cutting, a positive electrode sheet is obtained. A negative electrode material, graphite, conductive carbon black, thickener sodium carboxymethyl cellulose, and binder styrene-butadiene rubber are mixed in a mass ratio of 94:2:1:3. Using deionized water as a solvent, the mixture is adjusted to a uniform slurry with a solid content of 56%. This slurry is coated onto copper foil, dried in an oven at 80°C, and then rolled. After slitting and die-cutting, a negative electrode sheet is obtained. The above positive electrode sheet, separator, and negative electrode sheet are processed into a core through winding and hot pressing processes. The core is then packaged with polymer, filled with the electrolyte obtained in step (4), and processed through formation and capacity testing to produce a soft-pack lithium-ion battery.

[0111] Example 2 (1) Pretreatment of DTPMP (diethylenetriaminepentamethylenephosphonic acid) DTPMP (diethylenetriamine pentamethylphosphonic acid) powder and anhydrous THF solvent were added to a high-pressure reactor. The mixture was heated to 50°C with a stirring speed of 150 rpm and then bubbled through dry nitrogen (N2) for 23 hours. During this process, the moisture content must be monitored in real time to ensure that the system H2O ≤ 15 ppm.

[0112] (2) Sulfonation and neutralization reactions a. Pretreatment: Dissolve DTPMP in 15 L of anhydrous THF and transfer it to a glass-jacketed reactor. Control the temperature inside the glass-jacketed reactor at 20℃~25℃.

[0113] b. Sulfonation reaction: Under stirring speed of 500 rpm, concentrated sulfuric acid was slowly added in batches through a constant pressure dropping funnel, maintaining the temperature at 20℃~25℃ and reacting for 5 hours. The absence of free acid was confirmed by pH test paper (pH≥4). The mass ratio of DTPMP to concentrated sulfuric acid was 5:1.

[0114] c. Quenching and purification: The sulfonation reaction solution is quenched in pre-cooled deionized water, extracted with diethyl ether, and the aqueous phase is collected.

[0115] d. Neutralization reaction: Transfer the aqueous phase into the crystallization vessel, and slowly add LiOH powder and anhydrous ethanol while stirring, control the temperature at 20℃, and adjust the pH to about 7.

[0116] (3) Substitution reaction a. Substitution reaction: The material obtained in step (2) is placed in a reactor, the reactor is replaced with N2 three times, and C8F is added. 17 Liquid I was heated to 80°C under sealed conditions, with the stirring rate increased to 250 rpm, and refluxed for 12 hours to ensure that the residual DTPMP content was ≤0.5%. DTPMP and C8F 17 The molar ratio of I is 1:1.

[0117] b. Post-processing: The reaction solution obtained from the substitution reaction was transferred to a rotary evaporator, concentrated in a water bath at 450°C under a vacuum of ≤0.1 kPa, and the THF solvent was recovered to obtain the intermediate.

[0118] e. Cool the intermediate to -20°C, age for 4 hours and induce crystallization. Collect the white solid using a vacuum filter, and wash the filter cake multiple times with pre-cooled ether. Transfer the wet filter cake to a spray dryer and set the parameters as follows: inlet air temperature 120°C, outlet air temperature 65°C, atomization pressure 0.8 MPa, and nitrogen flow rate 10 m / s². 3 / h, dry until the moisture content is below 10ppm, then pass the dried material through a 200-mesh sieve to obtain a white microcrystalline powder, which is the additive. Subsequently, the additive is vacuum-sealed into an aluminum-plastic composite bag in a vacuum glove box for storage.

[0119] The chemical structural formula of the additive is shown in Formula IV: (IV) (4) Preparation of electrolyte In a vacuum glove box, the organic solvents ethylene carbonate EC, fluoroethylene carbonate EMC, and dimethyl carbonate DMC were mixed in a volume ratio of 3:5:2. Then, an appropriate amount of LiPF6 was added to make the concentration of LiPF6 1.2 mol / L. Fluoroethylene carbonate and the additives obtained in step (4) were then added. The mixture was aged at 40°C for 2 hours and then filtered through a 0.2 μm filter membrane to remove impurities to obtain the electrolyte. The mass content of the additives in the electrolyte was 1.5 wt%, and the mass content of fluoroethylene carbonate in the electrolyte was 2 wt%.

[0120] (5) Assembly of battery cells LiNi cathode material 0.8 Co 0.1 Mn 0.1 O2, conductive carbon black, and binder polyvinylidene fluoride are mixed in a mass ratio of 93:5:2. Using NMP (N-methylpyrrolidone) as a solvent, the mixture is adjusted to a uniform slurry with a solid content of 58%. The slurry is uniformly coated onto aluminum foil, dried in an oven at 85°C, and then rolled. After slitting and die-cutting, a positive electrode sheet is obtained. A negative electrode material, graphite, conductive carbon black, thickener sodium carboxymethyl cellulose, and binder styrene-butadiene rubber are mixed in a mass ratio of 94:2:1:3. Using deionized water as a solvent, the mixture is adjusted to a uniform slurry with a solid content of 56%. This slurry is coated onto copper foil, dried in an oven at 80°C, and then rolled. After slitting and die-cutting, a negative electrode sheet is obtained. The above positive electrode sheet, separator, and negative electrode sheet are processed into a core through winding and hot pressing processes. The core is then packaged with polymer, filled with the electrolyte obtained in step (4), and processed through formation and capacity testing to produce a soft-pack lithium-ion battery.

[0121] Example 3 Unlike Example 2, (2) Sulfonation and neutralization reactions a. Pretreatment: Dissolve DTPMP in 15 L of anhydrous THF and transfer it to a glass-jacketed reactor. Control the temperature inside the glass-jacketed reactor at 20℃~25℃.

[0122] b. Sulfonation reaction: Under stirring speed of 500 rpm, ClSO3H was slowly added through a constant pressure dropping funnel, the temperature was maintained at 20℃~25℃ and the reaction was carried out for 5 hours. The absence of free acid was confirmed by pH test paper (pH≥4). The mass ratio of DTPMP to concentrated sulfuric acid was 15:1.

[0123] c. Quenching and purification: The sulfonation reaction solution is quenched in pre-cooled deionized water, extracted with diethyl ether, and the aqueous phase is collected.

[0124] d. Neutralization reaction: Transfer the aqueous phase into the crystallization vessel, and slowly add LiOH powder and anhydrous ethanol while stirring, control the temperature at 20℃, and adjust the pH to about 7.

[0125] (3) Substitution reaction a. Substitution reaction: The material obtained in step (2) is placed in a reactor, the reactor is replaced with N2 three times, and C8F is added. 17 Liquid I was heated to 80°C under sealed conditions, with the stirring rate increased to 250 rpm, and refluxed for 12 hours to ensure that the residual DTPMP content was ≤0.5%. DTPMP and C8F 17 The molar ratio of I is 2:1.

[0126] b. Post-processing: The reaction solution obtained from the substitution reaction was transferred to a rotary evaporator, concentrated in a water bath at 450°C under a vacuum of ≤0.1 kPa, and the THF solvent was recovered to obtain the intermediate.

[0127] e. Cool the intermediate to -20°C, age for 4 hours and induce crystallization. Collect the white solid using a vacuum filter, and wash the filter cake multiple times with pre-cooled ether. Transfer the wet filter cake to a spray dryer and set the parameters as follows: inlet air temperature 120°C, outlet air temperature 65°C, atomization pressure 0.8 MPa, and nitrogen flow rate 10 m / s². 3 / h, dry until the moisture content is below 10ppm, then pass the dried material through a 200-mesh sieve to obtain a white microcrystalline powder, which is the additive. Subsequently, the additive is vacuum-sealed into an aluminum-plastic composite bag in a vacuum glove box for storage.

[0128] The chemical structural formula of the additive is shown in Formula V: (V) Example 4 Unlike Example 1, in (2) C8F 17 Replace I with C5F 11 I.

[0129] The chemical structural formula of the additive is shown in Formula VI: (VI) Example 5 Unlike Example 1, in (2) C8F 17 Replace I with C8H 17 I.

[0130] The chemical structural formula of the additive is shown in Formula VII: (VII) Example 6 Unlike Example 1, (4) the additive content in the electrolyte is 0.5 wt%.

[0131] Example 7 Unlike Example 1, (4) the additive content in the electrolyte is 1 wt%.

[0132] Example 8 Unlike Example 1, (4) the additive content in the electrolyte is 2wt%.

[0133] Example 9 Unlike Example 1, (4) the mass content of the additive in the electrolyte is 2.3 wt%.

[0134] Comparative Example 1 Unlike Example 1, no additives are added in (4).

[0135] Performance testing: (1) The chemical structure of the additive was determined by high-resolution mass spectrometry (HRMS), elemental analysis and nuclear magnetic resonance spectroscopy.

[0136] (2) The particle size testing method for additives shall refer to GB / T 19077-2016. The cumulative particle size distribution based on volume can be conveniently determined using a laser particle size analyzer, such as the Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK. D 10 D represents the particle size at which the cumulative particle size distribution percentage reaches 10%. 50 D represents the particle size at which the cumulative particle size distribution percentage reaches 50%. 90 This indicates the particle size corresponding to a cumulative particle size distribution percentage of 90%.

[0137] (3) The ionic conductivity of the additives was determined by AC impedance method.

[0138] (4) The mass content of free hydrofluoric acid and water in the electrolyte is determined by potentiometric titration or ion chromatography.

[0139] (5) Electrochemical performance: The rated capacity test of the battery cell should be conducted at an ambient temperature of (25±1)℃. During the test, the battery should first be charged using a standard charging program (usually constant current charging at 0.2C to 4.2V, then constant voltage charging to a current ≤0.05C). After resting, it should be discharged at a constant current of 0.2C to the discharge termination voltage specified by the manufacturer (usually 3.0V for NCM811 / graphite systems). The discharge capacity must reach or exceed the nominal rated capacity, and to eliminate the irreversible effects of the first charge and discharge, this test is usually performed on the second or third standard cycle.

[0140] The cycle life test for the battery cell involves continuous, specific charge-discharge cycles at a specified temperature (typically 25°C) (charging to 4.2V with a constant current of 1C, then switching to constant voltage, followed by discharging to the cutoff voltage with a constant current of 1C). During the test, after a certain number of cycles (e.g., every 50 cycles), a standard capacity verification cycle (charge-discharge at 0.2C) is inserted to calibrate and record the current actual capacity. Here, 200 charge-discharge cycles are performed at 25°C and 45°C within the 3.0V~4.2V discharge range, using a 1C rate. The measured capacity retention rates are the cell's room temperature cycle retention rate and high temperature cycle retention rate.

[0141] Under a specified ambient temperature (e.g., 25°C) and a specific state of charge (SOC, typically 50%), a short-duration high-current pulse (e.g., a 1C discharge current lasting 10 seconds) is applied to the stabilized battery. By accurately measuring the terminal voltage (U1) just before the pulse begins and the terminal voltage (U2) at the end of the pulse, the DC internal resistance is calculated using the formula DCR = (U1 - U2) / I, where I is the pulse current.

[0142] The performance of the additive materials, electrolytes and battery cells prepared in the above examples and comparative examples was measured. Examples 1 to 9 are denoted as S1 to S9, and Comparative Example 1 is denoted as D1. The measurement results are shown in Table 1.

[0143] Table 1. Comparison of Examples and Comparative Cases

[0144] According to the test data from Examples 1 to 9, the additives of this application, when added to the electrolyte, on the one hand, enable the electrolyte to actively adsorb transition metal ions, reducing the dissolution of transition metal ions and their migration to the negative electrode, thereby effectively suppressing the negative electrode interface failure problem caused by the dissolution of transition metal ions during battery cycling; on the other hand, they suppress the catalytic ability of transition metal ions on negative electrode side reactions, which is beneficial to suppressing the occurrence of side reactions, thereby improving the room temperature and high temperature cycle performance of the battery cell, and also having a low DC internal resistance value. In addition, the electrolyte of this application has a low mass content of free hydrofluoric acid and water, which is beneficial to improving the cleanliness of the electrolyte, thereby achieving high cycle life, excellent rate performance and high temperature safety of the battery cell.

[0145] In Examples 6-9, the electrochemical performance of the battery cell can be adjusted by changing the content of the additive in the electrolyte. In Example 6, the additive content was too low, resulting in limited ability of the electrolyte to suppress transition metal elements in the cathode material, and a slight decrease in the capacity and capacity retention of the battery cell. In Example 9, the additive content was too high, resulting in an increase in the viscosity of the electrolyte system, a slight decrease in the ionic conductivity of the electrolyte, and a slight decrease in the capacity and capacity retention of the battery cell.

[0146] Comparative Example 1 uses a conventional electrolyte to prepare battery cells. The cathode material is prone to lattice oxygen loss under long-term cycling or high voltage, leading to the loss of transition metal ions (Mn) in the cathode material. 2+ Ni 2+ and Co 2+ At least one of the following (e.g., lithium dendrites) dissolves, and the dissolved ions readily migrate to the negative electrode. These transition metal ions have strong catalytic activity and will catalyze the decomposition of the electrolyte at the negative electrode interface, leading to an increase in the decomposition products of the electrolyte at the negative electrode interface and an increase in interfacial impedance. The high-impedance negative electrode interface is prone to inducing the formation of lithium dendrites, which not only consumes active lithium ions but may also cause internal short circuits in the battery, resulting in a significant increase in the free hydrofluoric acid and water content of the battery cells, a significant deterioration in the battery's cycle retention rate at both room temperature and high temperature, and a significant increase in the DC internal resistance.

[0147] The above description, based on the embodiments shown in the drawings, details the structure, features, and effects of this application. The above description is only a preferred embodiment of this application, but this application does not limit the scope of implementation to what is shown in the drawings. Any changes made in accordance with the concept of this application, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and drawings, should be within the protection scope of this application.

Claims

1. A battery cell, characterized by, The battery monomer includes a positive electrode, a negative electrode, a diaphragm and an electrolyte, the positive electrode includes a positive electrode material, the positive electrode material includes a transition metal element, the transition metal element includes at least one of Mn, Ni and Co, the electrolyte includes an organic solvent and an additive, and the additive includes a chemical formula as shown in formula I: （Ⅰ） In formula I, R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10are each independently selected from the group consisting of OH, C n H 2n+1 , C n H 2n+1-m X m and SO3M, M is Li or Na, X is halogen, n = 1-10, m is 0-(2n+1), and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10is selected from SO3M.

2. The battery cell of claim 1, wherein, each of said R1and R2is independently selected from C n H 2n+1-m X m and any one of SO3M.

3. The battery cell of claim 1, wherein, said R1is selected from any one of SO3Li and C8F 17 said R2is selected from any one of SO3Li and C8F 17 and R1and R2are different, said R3, R4, R5, R6, R7, R8, R9and R10are all OH.

4. The battery cell of claim 1, wherein, The mass content of the additive in the electrolyte is 1wt%-2wt%.

5. The battery cell of claim 1, wherein, The additive has a crystal structure.

6. The battery cell of claim 1, wherein, The volume particle size distribution D of the additive 10 is 3 μm to 8 μm; and / or The volume particle size distribution D of the additive 50 is 18 μm to 28 μm; and / or The volume particle size distribution D of the additive 90 is 45 μm to 70 μm.

7. The battery cell of claim 1, wherein, During the charging and discharging process of the battery monomer, each of the additives can capture 2-5 transition metal ions.

8. The battery cell of claim 1, wherein, The conductivity of the electrolyte is 10mS / cm-11mS / cm; and / or The mass content of free hydrofluoric acid in the electrolyte is 2ppm-10ppm; and / or The mass content of water in the electrolyte is 3ppm-6ppm.

9. The battery cell of claim 1, wherein, The positive electrode material includes at least one of high-nickel ternary positive electrode material, transition metal oxide positive electrode material, olivine-type positive electrode material and sodium transition metal oxide positive electrode material.

10. The battery cell according to claim 1 or 9, characterized in that, The positive electrode material includes at least one of nickel-cobalt-manganese lithium acid positive electrode material, nickel-cobalt-aluminum lithium acid positive electrode material, lithium cobaltate positive electrode material, manganese-iron lithium phosphate positive electrode material, sodium manganese-iron-copper acid positive electrode material and sodium nickel-iron-manganese acid positive electrode material.

11. The battery cell of claim 1, wherein, The organic solvent includes at least one of vinyl carbonate, fluorinated vinyl carbonate, dimethyl carbonate, propylene carbonate, chain carbonate and carboxylic acid ester.

12. The battery cell of claim 1, wherein, The electrolyte further includes an electrolyte salt, and the electrolyte salt includes at least one of lithium salt, sodium salt, potassium salt and magnesium salt.

13. A method of producing a battery cell, characterized by, The method includes the following steps: Dehydrating diethylene triamine pentaformyl phosphonic acid to obtain a first precursor; Substituting the first precursor with a hydrophobic compound to obtain a second precursor, the hydrophobic compound including at least one of alkyl and halogen-substituted alkyl; Reacting the second precursor with a halogen-substituted sulfonic acid compound and then performing crystallization treatment to obtain an additive; Mixing the additive and an organic solvent to obtain an electrolyte; Providing a positive electrode, a negative electrode and a diaphragm, the positive electrode including a positive electrode material, the positive electrode material including a transition metal element, the transition metal element including at least one of Mn, Ni and Co, and winding or laminating the positive electrode, the negative electrode and the diaphragm to obtain an electric core assembly; Assembling the electric core assembly and a shell to obtain a battery module; Injecting the electrolyte into the battery module to obtain a battery monomer.

14. A battery device characterized by comprising: The battery device includes one or more of a battery module, a battery pack and an energy storage battery formed by the battery monomer of any one of claims 1-12 or the preparation method of the battery monomer of claim 13.

15. An electrical device, comprising: The electric device includes the battery device of claim 14, and the battery device is used to provide electric energy.

16. An energy storage device, characterized by The energy storage device includes the battery device of claim 14, and the battery device is used to store electric energy.

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