Electrolytes, batteries, battery packs, and battery systems for lithium (sodium) ion batteries

Abstract

This invention discloses an electrolyte, battery, battery pack, and battery system for a lithium (sodium) ion battery, comprising an ionic electrolyte containing lithium borate ester (sodium salt) or lithium imine ester (sodium salt); an isoelectric point solvent of triethylamine ester, triethanolamine ester, borate ester, or phosphate ester; electrolyte 20%–50%, solvent 50%–80%. The ionic electrolyte developed in this invention is an organic compound with no ignition point and high safety, and can be used under operating conditions with voltages greater than 5 volts. The voltage of a typical lithium-ion battery is 3.4 volts. Furthermore, the electrolyte used in this invention is used in very small quantities, thus reducing overall cost and resulting in higher economic benefits. The zwitterionic polar solvent of this invention separates molecules into ions based on the charge carried by the material molecules. Due to its isoelectric point, it provides fast charging and discharging capabilities, increasing the ion transfer rate by 2-3 times or more than that of typical carbonate solvents.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electrolyte, battery, battery pack and battery system for a lithium (sodium) ion battery. Background Technology

[0002] Lithium (sodium)-ion batteries have become the primary power source for portable electronic products, electric vehicles, and energy storage systems. Sodium-ion batteries, which were commercialized later, are also a major power source for applications such as energy storage systems. Therefore, the production and market application of both types of batteries are constantly expanding, and related technologies are developing rapidly. The main components of a lithium-ion battery include the following: The positive electrode is usually made of lithium metal oxides (such as lithium nickel, lithium cobalt, lithium manganese, lithium nickel cobalt manganese, lithium iron phosphate, etc.) and is used to store and release lithium ions. The negative electrode is usually made of carbon materials (such as graphite) and is used to store and release lithium ions. The electrolyte is the medium through which lithium ions move within the battery, including organic solvent-based electrolytes: the main components are organic solvents such as carbonates (ethylene carbonate, dimethyl carbonate, etc.) and lithium salts. Advantages include high ionic conductivity and good electrochemical stability. Disadvantages include flammability, spontaneous combustion, and relatively poor safety. Solid-state electrolytes are based on inorganic solid materials such as ceramics and glass. Advantages include high safety and suppression of dendritic lithium growth; disadvantages include lower ionic conductivity and higher cost. Polymer electrolytes use polymer materials as a matrix and contain lithium salts. Their advantages include high mechanical strength and flexible shape design; their disadvantage is relatively low ionic conductivity. Ionic liquid electrolytes use non-flammable ionic liquids as solvents and contain lithium salts. Their advantages include high safety and good electrochemical stability; their disadvantage is lower ionic conductivity.

[0003] Sodium-ion batteries typically consist of a positive electrode material, a negative electrode material, and an electrolyte. The combination of these materials forms the battery's two electrodes and its conductive components. Common positive electrode materials include oxides, such as sodium oxide and iron oxide, or compounds with high sodium content. These materials can insert or release sodium ions, undergoing chemical reactions during charging and discharging. Common negative electrode materials include graphite and carbon materials. These materials can absorb and release sodium ions, also participating in the chemical reactions during charging and discharging. The electrolyte plays a crucial role in sodium-ion batteries, conducting sodium ions while preventing direct contact between the positive and negative electrodes to prevent short circuits and battery malfunctions. Common sodium-ion battery electrolytes include liquid electrolytes and solid electrolytes. Liquid electrolytes consist of organic solvents (such as carbonates and acrylonitrile) and dissolved salts (such as fluorates and sulfates). These electrolytes generally exhibit good conductivity and electrochemical stability. Solid electrolytes: Solid electrolytes have become a research hotspot in recent years. They are typically composed of polymers or inorganic materials, such as polymer electrolytes and oxide electrolytes. Solid electrolytes offer higher safety and stability compared to liquid electrolytes and can meet the requirements of high energy density and long lifespan.

[0004] Electrolyte is one of the four key materials in lithium-ion or sodium-ion batteries. Traditional electrolytes suffer from overheating and combustion issues, as well as poor high-voltage tolerance, making it a crucial area for improvement. Among various energy storage batteries, lithium-ion batteries offer the advantage of high energy density, thus finding applications in energy storage and electric vehicle products.

[0005] The four key materials that make up a lithium battery are the positive electrode material, the negative electrode material, the electrolyte, and the separator. Among them, the electrolyte is often referred to as the blood of a lithium battery, responsible for conducting ions between the positive and negative electrodes. However, traditional electrolytes using organic solvents have problems such as low thermal stability, high volatility, and high flammability. Once an electric vehicle is involved in a collision, the battery installed in the vehicle may experience thermal runaway, leading to spontaneous combustion, or even explosion and fire.

[0006] To achieve high energy density in batteries, it is often necessary to increase the operating voltage. Traditional organic electrolytes are prone to instability at high voltages, leading to battery performance degradation and a reduction in the number of charge-discharge cycles. To address the problems of traditional organic electrolytes, the development of solid-state lithium batteries using oxide or sulfide electrolytes is generally the approach. However, solid-state lithium batteries face challenges such as high cost and poor solid-state interface bonding, hindering commercialization and widespread adoption. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem that the electrolyte of existing lithium (sodium) ion batteries is prone to instability under high voltage, which leads to battery performance degradation and a decrease in the number of charge-discharge cycles. The invention provides an electrolyte, battery, battery pack and battery system for lithium (sodium) ion batteries.

[0008] An electrolyte for a lithium (sodium) ion battery includes an ionic electrolyte containing a lithium borate ester (sodium salt) or an imine ester (sodium salt); an isoelectric point solvent of triethylamine ester, triethanolamine ester, borate ester, or phosphate ester; 20%–50% electrolyte and 50%–80% solvent.

[0009] The electrolytes of this invention, as shown in Table 1, include 13 types, including lithium borate ester (sodium salt) and lithium imine ester (sodium salt). Specifically, the ionic electrolyte contains at least one of the following components: difluorobutenedioic acid boric acid (lithium / sodium), difluorosuccinic acid boric acid (lithium / sodium), difluoromalonide boric acid (lithium / sodium), difluorodiacetic acid boric acid (lithium / sodium), butenedioic acid diethylimide (lithium / sodium), succinic acid diethylimide (lithium / sodium), malonide diethylimide (lithium / sodium), diacetate diethylimide (lithium / sodium), dimethyl diacetate diimide (lithium / sodium), diethyl diacetate diethylimide (lithium / sodium), diethylene diacetate diethylimide (lithium / sodium), diethylene diacetate diethylimide (lithium / sodium), diethylene diacetate diethylimide (lithium / sodium), and diethylene diacetate diethylimide (lithium / sodium).

[0010] Electrolytes are substances that can generate free ions and conduct electricity in a molten or solution state. The substances listed in Table 1 can all generate lithium (sodium) ions in solution, thus allowing ions to transport between the positive and negative electrodes without combustion, providing fire and explosion protection.

[0011] Table 1. Flame-retardant and explosion-proof concentrated (lithium / sodium) electrolyte

[0012]

[0013]

[0014] The solvents used in this invention are solvents with zero flash point, isoelectric point, and high voltage resistance, as listed in Table 2, including triethylamine ester, triethanolamine ester, borate ester, phosphate ester, etc., totaling 12 types. Specifically, the isoelectric point solvent contains at least one of the following components: triethylamine triacetate, triethylamine butenedioate acetate, tri(butenedioate)bis(triethylamine), triethylamine (fluoro / chloro)tricarboxylic acid propyl ester, triethylamine tricarboxylic acid propyl ester, triethylamine triacetate, triethanolamine borate ester, triethanolamine phosphate, glyceryl borate, glyceryl phosphate, glyceryl aminotriacetate, and triethyl aminotriacetate.

[0015] Zero flash point means it will not burn. The isoelectric point is the pH value of a solution when the number of positive and negative charges on the molecules are equal. The solvent of this invention is a polar molecule with an isoelectric point, carrying both positive and negative charges, making it an excellent ion conductor.

[0016] Table 2. Isoelectric Point and Safety of Ionic Solvents

[0017]

[0018]

[0019] The zwitterionic polar solvent of this invention separates molecules into ions based on the different charges carried by the material molecules. Due to its isoelectric point and rapid charging and discharging capabilities, it can increase the ion transfer rate by 2-3 times or more than that of general carbonate solvents. An example of a zwitterionic substance with an isoelectric point is an amino acid (RNH2R'COOH), whose molecule contains both an amino group (positively charged) and an acid group (negatively charged). In acidic solutions, the amino groups in the molecule react with the acid and dissolve; in alkaline solutions, the acid groups in the molecule react with the base and dissolve, thus exhibiting an isoelectric point, i.e., zwitterionicity.

[0020] Based on the above principles, the solvent of this invention also has the same properties. Furthermore, the isoelectric point solvent can accept both positively and negatively charged ions, and the ion transfer rate is relatively fast. The electrolyte in a typical lithium-ion battery is lithium hexafluorophosphate (LiPF6), and the ratio of lithium hexafluorophosphate to carbonate solvent is 1:7, with approximately 1.3 moles used per liter.

[0021] The concentrated electrolyte and solvent ratio of this invention is 20%–50% electrolyte and 50%–80% solvent. This achieves ion transport efficiency, thus reducing the amount of solvent used.

[0022] The electrolyte of this invention comprises an electrolyte selected from at least one concentrated electrolyte (A1-A13) in Table 1, and a solvent selected from at least one isoelectric point solvent (B1-B12) in Table 2. This allows for the formulation of liquid, solid, or gel-like lithium (sodium) ion batteries. Specifically, the electrolytes in Table 1 are all solid, and the solvents in Table 2 are divided into three types: solid, paste / wax (gel), and paste / oil (liquid). Combining the electrolyte with a solid solvent produces a solid electrolyte, which can be used to produce solid-state batteries. Combining the electrolyte with a gel solvent produces a gel electrolyte, which can be used to produce gel batteries. Combining the electrolyte with a liquid solvent produces a liquid electrolyte, which can be used to produce liquid batteries.

[0023] When the electrolytes in Table 1 are mixed with the solvents in Table 2, they can be heated and stirred until homogeneous. The solid electrolyte remains solid after cooling, the colloidal electrolyte remains colloidal after cooling, and the liquid electrolyte remains liquid after cooling.

[0024] Solid electrolytes can be heat-printed or pressed into sheets to conform to the battery shape for assembly and processing. Colloidal and liquid electrolytes can also be used in battery processing via filling or injection. Furthermore, suitable additives can be added during electrolyte formulation, such as positive electrode protection additives, negative electrode film-forming additives, overcharge protection additives, and flame retardant additives.

[0025] The electrolyte and electrolyte solution of this invention are both safe and will not explode or burn when exposed to water, so production does not need to be carried out in a dry room.

[0026] A lithium (sodium) ion battery and / or battery pack comprising any one of the above-mentioned electrolytes. The electrolyte is formed by mixing the electrolyte and solvent in a specific ratio and then stirring the mixture, wherein the heating temperature is controlled at 30–50°C during the stirring process.

[0027] A lithium (sodium) ion battery system having the ion battery or battery pack described above.

[0028] The beneficial effects of this invention are:

[0029] 1. The present invention uses an electrolyte with flame-retardant and explosion-proof properties, combined with a solvent with isoelectric point to obtain an electrolyte. Compared with traditional electrolytes, it only requires electrolyte and solvent, without the need for additives, to achieve ion transport. At the same time, the overall solvent usage can also be reduced. It has better flame-retardant and explosion-proof effects and can be applied to operating conditions with voltage greater than 5 volts.

[0030] 2. This invention develops an ionic electrolyte, which is an organic compound with no ignition point and high safety, and can be used in operating conditions with voltages greater than 5 volts. The voltage of a typical lithium-ion battery is 3.4 volts. Furthermore, the electrolyte used in this invention is used in very small quantities, thus reducing overall cost and resulting in higher economic benefits.

[0031] 3. The zwitterionic polar solvent of the present invention separates molecules into ions based on the charge carried by the material molecules. Due to its fast charging and discharging capabilities at its isoelectric point, it can increase the ion transfer rate by 2-3 times or more than that of general carbonate solvents. Attached Figure Description

[0032] Figure 1 Example of a flame-retardant and explosion-proof concentrated (lithium / sodium) electrolyte process - difluorobutenedioic acid boric acid (lithium /

[0033] sodium);

[0034] Figure 2 Example of ionic solvent processes with isoelectric point and safety - triethylamine triacetate; Detailed Implementation

[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0036] Example 1

[0037] The synthesis methods of flame-retardant and explosion-proof concentrated (lithium / sodium) electrolytes are shown in Table 3:

[0038]

[0039]

[0040]

[0041]

[0042] like Figure 1 As shown, taking A1 in Table 3 as an example, the synthesis reaction process is as follows: Figure 1 As shown. Take 87.8 kg of fluoroboric acid and 116 kg of butenadic acid, each in one molar equivalent, and place them in a reaction vessel. Stir and heat to 120°C for approximately 1-2 hours to remove two molecules of hydrofluoric acid (HF), completing the esterification. Then, add one molar equivalent of lithium hydroxide (24 kg) or sodium hydroxide (40 kg) to the reaction vessel, and heat to 150-200°C to remove one molecule of water (H₂O), completing the reaction and obtaining difluorobutenadic boric acid (lithium / sodium).

[0043] Figure 1 The chemical reaction formula is as follows:

[0044] HBF4+HO2CCHCHCO2H→BF2O2CCHCHCO2H+2HF

[0045] BF2O2CCHCHCO2H+LiOH→BF2O2CCHCHCO2Li+H2O

[0046] BF2O2CCHCHCO2H+NaOH→BF2O2CCHCHCO2Na+H2O

[0047] Example 2

[0048] The synthesis methods of ionic solvents with isoelectric point and safety are shown in Table 4.

[0049]

[0050]

[0051]

[0052] Taking B1 in Table 4 as an example, the synthesis reaction process is as follows: Figure 2 As shown. Take three molar equivalents of glacial acetic acid (180 kg) and one molar equivalent of triethanolamine (149 kg), put them into a reaction vessel and stir. Heat to 120°C and react for about 1-2 hours to remove three molecules of water, thus completing the reaction and obtaining triethylamine triacetate.

[0053] Figure 2 The chemical reaction formula is as follows:

[0054] 3CH3COOH+N(CH2CH2OH)3→N(CH2CH2COOCH3)3+3H2O

[0055] Example 3

[0056] A lithium (sodium) ion battery and / or battery pack having any of the above-mentioned electrolytes.

[0057] The electrolytes obtained based on the electrolytes and solvents in Examples 1 and 2 are analyzed below.

[0058] The electrolyte is selected from at least one concentrated electrolyte (A1-A13) in Table 1, and the solvent is selected from at least one isoelectric point solvent (B1-B12) in Table 2. After mixing in the specified proportions, the mixture is heated (30°C) and stirred until homogeneous.

[0059] Experimental Examples 1-15 were obtained and subjected to short-circuit, overcharge, heavy object impact, and temperature shock tests according to the UL1642 lithium battery safety standard. The results were observed to determine if the battery would ignite, burn, or exhibit a crackling or explosion-like sound. Specific details are shown in Table 5 below.

[0060] serial number electrolytes solvent state fire prevention Explosion-proof Experimental Example 1 A1＝20％ B1＝80％ ointment liquid pass pass Experiment Example 2 A1＝50％ B1＝50％ ointment liquid pass pass Experimental Example 3 A2＝30％ B2＝70％ ointment liquid pass pass Experiment Example 4 A2＝40％ B2＝60％ ointment liquid pass pass Experimental Example 5 A3＝20％ B2＝80％ ointment liquid pass pass Experimental Example 6 A4＝30％ B3＝70％ solid colloidal pass pass Experimental Example 7 A5＝50％ B4＝50％ ointment liquid pass pass Experimental Example 8 A6＝20％ B5＝80％ ointment liquid pass pass Experimental Example 9 A7＝40％ B6＝60％ Solid wax pass pass Experimental Example 10 A8＝50％ B7＝50％ Solid wax pass pass Experimental Example 11 A9＝20％ B8＝80％ Solid wax pass pass Experimental Example 12 A10＝30％ B9＝70％ ointment liquid pass pass Experimental Example 13 A11＝40％ B10＝60％ ointment liquid pass pass Experimental Example 14 A12＝20％ B11＝80％ Solid wax pass pass Experimental Example 15 A13＝50％ B12＝50％ ointment liquid pass pass

[0061] As shown in Table 5, the ionic electrolyte developed in this invention is an organic compound with no ignition point and high safety, and can be used in operating conditions with voltages greater than 5 volts. The voltage of a typical lithium-ion battery is 3.4 volts. Furthermore, the electrolyte used in this invention requires very little quantity, thus reducing overall cost and resulting in higher economic benefits. The zwitterionic polar solvent of this invention separates molecules into ions based on the charge carried by the material molecules. Due to its isoelectric point and fast charging and discharging capabilities, it can increase the ion transfer rate by 2-3 times or more than that of typical carbonate solvents.

[0062] Example 4

[0063] A lithium (sodium) ion battery system having the ion battery or battery pack described above.

[0064] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An electrolyte for lithium / sodium ion batteries, characterized in that: Ionic electrolyte containing borate lithium salt sodium / salt or imidate lithium salt / sodium salt; isoelectric point solvent of triethylamine ester, triethanolamine ester, borate or phosphate; electrolyte 20%~50%, solvent 50%~80%; The ionic electrolyte contains at least one of the following components: lithium / sodium difluorobutene dioic acid borate, lithium / sodium difluorosuccinic acid borate, lithium / sodium difluoromalic acid borate, lithium / sodium difluoro diacetic acid borate, lithium / sodium butene dioic acid diethyl imide, lithium / sodium succinic acid diethyl imide, lithium / sodium malonic acid diethyl imide, lithium / sodium diacetic acid diethyl imide, lithium / sodium diacetic acid dimethyl imide, lithium / sodium diacetic acid diethyl imide, lithium / sodium diacetic acid ethylene imide, lithium / sodium diacetic acid propylene imide, lithium / sodium diacetic acid diethylene imide; The isoelectric point solvent contains at least one of the following components: triacetate triethylamine, butene dioic acid acetate triethylamine, tri(butene dioic acid) bis(triethylamine), fluorine / chlorine propyl triethylamine tricarboxylate, propyl triethylamine tricarboxylate, amine-based triethylamine triacetate, triethanolamine phosphate, glycerol borate, glycerol phosphate, amine-based glycerol triacetate, amine-based triethyl triacetate.

2. The electrolyte of lithium / sodium ion battery according to claim 1, characterized in that: Also included are additives, which are one or more of positive electrode protection additives, negative electrode film forming additives, overcharge prevention additives, and flame retardant additives.

3. The electrolyte of lithium / sodium ion battery according to claim 1, characterized in that: The electrolyte is solid, gel or liquid.

4. A lithium / sodium-ion battery and / or battery pack, characterized in that: Having an electrolyte as claimed in any one of claims 1~3.

5. A lithium / sodium-ion battery system, characterized by: Having an ionic battery or battery pack as claimed in claim 4.

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