Closed valve control type power battery with high energy and high charging efficiency

Abstract

The invention relates to the technical field of batteries, and discloses a high-energy high-charging-efficiency closed valve control type power battery, which comprises a battery, a positive electrode region is arranged in one side of the battery, and a negative electrode region is arranged in the other side of the battery; a positive electrode material used by the battery is a lithium iron phosphate composite material, the positive electrode material comprises lithium iron phosphate, a high-conductivity carbon coating and a nano-composite, and the positive electrode material is located in a positive electrode region in the battery; a negative electrode material used by the battery is a silicon-based composite material, the negative electrode material comprises nanometer silicon and graphite, or silicon particles are compounded with a conductive polymer material, and the negative electrode material is located in a negative electrode area in the battery. By adopting an optimized electrolyte formula (such as an improved lithium salt and high-conductivity solvent mixture), the ionic conductivity of the battery can be remarkably improved. In the high-current charging process of the battery, the internal resistance of the electrolyte is reduced, and the charging rate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and specifically to a sealed valve-controlled power battery with high energy and fast charging efficiency. Background Art

[0002] With the rapid development of application fields such as electric vehicles and energy storage systems, power batteries with high energy density and fast charging have become the focus of research. The charging efficiency, energy density, and service life of batteries directly affect the performance and economy of these applications. In the development of battery technology, sealed valve-controlled power batteries, as an advanced battery design, have gradually received extensive attention. Through a sealed design and an internal valve control system, it effectively controls the pressure inside the battery, prevents the battery from being damaged due to overheating or overcharging, and ensures the stable operation of the battery during high-power charging.

[0003] However, many existing batteries are prone to phenomena such as too high internal resistance and electrolyte polarization during fast charging, resulting in low charging efficiency and even causing battery overheating, expansion, or other safety hazards. Although the electrolytes and conductive materials used in traditional batteries can meet basic requirements, they often cannot maintain a low internal resistance during high-power charging, restricting the charging rate and the overall efficiency of the battery. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a sealed valve-controlled power battery with high energy and fast charging efficiency, solving the problem that although the electrolytes and conductive materials used in traditional batteries can meet basic requirements, they will restrict the charging rate.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A sealed valve-controlled power battery with high energy and fast charging efficiency, including a battery. On one side inside the battery, there is a positive electrode region, and on the other side inside the battery, there is a negative electrode region; The positive electrode material used in the battery is a lithium iron phosphate composite material, where the positive electrode material includes lithium iron phosphate, a high-conductivity carbon coating, and a nano-composite. The positive electrode material is located in the positive electrode region inside the battery; The negative electrode material used in the battery is a silicon-based composite material, where the negative electrode material includes nano-silicon and graphite, or includes a composite of silicon particles and a conductive polymer material. The negative electrode material is located in the negative electrode region inside the battery.

[0006] Preferably, the positive electrode material includes 30% to 60% of lithium iron phosphate, 10% to 30% of the high-conductivity carbon coating, and 10% to 30% of the nano-composite. The nano-composite is perovskite; The negative electrode material contains 70% to 90% of nano-silicon and 10% to 30% of graphite, or contains silicon particles compounded with 10% to 15% of a conductive polymer material.

[0007] Preferably, the electrolyte used in the battery is an organic solvent solution containing a lithium salt. The lithium salt is lithium hexafluorophosphate, lithium tetrafluoroborate or lithium trifluoromethanesulfonate, and the concentration of the lithium salt is 1.0M to 1.5M; The organic solvent of the electrolyte is a mixture of dimethyl carbonate, ethylene carbonate and propylene carbonate. The mass ratio of each component in the mixture is 40% to 60% of ethylene carbonate, 30% to 50% of dimethyl carbonate and 10% to 20% of propylene carbonate.

[0008] Preferably, the electrolyte in the battery further contains 10% to 15% of nano-particles or highly conductive polymer materials. The nano-particles are alumina, titanium oxide or silicon dioxide, and the highly conductive polymer materials are polyaniline or polypyrrole.

[0009] Preferably, the positive electrode material and the negative electrode material in the battery are connected through the electrolyte and the separator. The separator is a polyolefin-based material with permeability. The porosity of the separator is 40% to 60%, and the thickness is 20μm to 30μm.

[0010] Preferably, the conductive additive used in the battery is graphene, carbon nanotubes or a composite material of graphene and carbon nanotubes. The mass ratio of the composite material is 2% to 10% of the negative electrode material.

[0011] Preferably, the battery uses an electrolyte with high conductivity and low internal resistance. The internal resistance of the electrolyte is less than 50mΩ at 20°C and can maintain low-temperature stability when the charging current reaches 1C.

[0012] Preferably, the thickness of the electrolyte layer between the positive electrode region and the negative electrode region of the battery is 10μm to 20μm and has ionic conductivity. The internal resistance of the battery is less than 20mΩ.

[0013] Preferably, a preparation method for a sealed valve-regulated power battery with high energy and fast charging efficiency includes the following steps: Step 1: Prepare the positive electrode material and the negative electrode material Preparation of the positive electrode material: Select lithium iron phosphate as the base material and modify it by doping elements such as vanadium, molybdenum or chromium. The doping ratio is 0.5% to 5%, and the particle diameter of the positive electrode material is 200nm to 300nm; Preparation of the negative electrode material: A silicon-based composite material is used as the anode material, and the material is composed of 90% to 95% of nano-silicon particles and 5% to 10% of graphite. The average diameter of the silicon particles is 100 nm; Step 2, surface modification of the positive and negative electrode materials The positive electrode material is modified by high-temperature nitridation method to coat a layer of highly conductive carbon material on its surface; For the silicon-based composite anode material, a silicon nitride layer is coated on its surface by chemical vapor deposition method, and the thickness of the silicon nitride is 30 nm to 50 nm; Step 3, preparation of the electrolyte The electrolyte is composed of lithium hexafluorophosphate, lithium tetrafluoroborate or lithium trifluoromethanesulfonate. The concentration of the lithium salt is 1.0 M to 1.5 M. A mixed solution of dimethyl carbonate and ethylene carbonate is selected as the solvent, and the solvent ratio is 40% to 60% of EC and 40% to 60% of DMC; at the same time, 1% to 2% of an ionic conductive additive is added; Step 4, preparation of the separator A polyolefin material is used to prepare the separator. The polypropylene nanofibers are combined with the polyethylene film by electrospinning technology. The porosity is 50% to 70%, and the thickness is 15 μm to 25 μm; Step 5, combination of the positive and negative electrode materials and the electrolyte The positive electrode material and the negative electrode material are connected through the electrolyte and the separator, and a stacked structure design is adopted to maximize the electrode area of the positive and negative electrodes; Step 6, assembly of the battery cell The positive and negative electrodes, the separator, the electrolyte and the battery management BMS system are combined to form a battery cell, and the battery shell is sealed with an aluminum alloy material.

[0014] Preferably, the treatment temperature in step 2 is 700 °C to 800 °C, and the treatment time is 4 to 6 hours.

[0015] The present invention provides a sealed valve-regulated power battery with high energy and fast charging efficiency. It has the following beneficial effects: 1. By adopting an optimized electrolyte formula (such as a mixture of modified lithium salt and highly conductive solvent), the present invention can significantly improve the ionic conductivity of the battery. During the high-current charging process of the battery, the internal resistance of the electrolyte is reduced, and the charging rate is increased.

[0016] 2. The conductive additive (such as nanoparticles or conductive polymer materials) in the electrolyte of the present invention can further reduce the polarization phenomenon of the battery, so as to maximize the charging efficiency on the premise of ensuring the safety of the battery.

[0017] 3. The present invention significantly improves the cycle stability of the battery by adopting nanotechnology and composite materials (such as the negative electrode composed of composite nanosilicon and carbon materials). The optimization of the materials enables the battery to maintain a low internal resistance during multiple charge and discharge processes, thereby reducing the energy loss during charge and discharge. In addition, the comprehensive optimization of the positive and negative electrode materials, conductive additives, and electrolyte of the battery reduces the side reactions during charge and discharge, improving the cycle life of the battery.

[0018] 4. By improving the positive and negative electrode materials, especially by adopting composite material technology (such as the composite of perovskite and lithium iron phosphate), the energy density of the battery of the present invention has been significantly increased. The new composite material can improve the battery's ability to store charge, while also maintaining good thermal stability and structural stability. This enables the battery to store more energy in the same volume or weight, providing users with a longer battery life, especially suitable for high-power applications such as electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a perspective view of a sealed valve-regulated power battery with high energy and fast charging efficiency according to the present invention; Figure 2 is an energy spectrum schematic diagram of the lithium salt of the present invention; Figure 3 is a schematic diagram of the conductive polymer material of the present invention; Figure 4 is a schematic diagram of silicon before charging the power battery of the present invention; Figure 5 is a schematic diagram of lithium ions after charging the power battery of the present invention; Figure 6 is a flowchart of a method for preparing a sealed valve-regulated power battery with high energy and fast charging efficiency according to the present invention.

[0020] Wherein, 1. Battery; 2. Positive electrode region; 3. Negative electrode region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Please refer to the attached Figure 1 - attached Figure 5 , the embodiment of the present invention provides a sealed valve-regulated power battery with high energy and fast charging efficiency, including a battery 1, a positive electrode region 2 is arranged inside one side of the battery 1, and a negative electrode region 3 is arranged inside the other side of the battery 1; The positive electrode material used in Battery 1 is a lithium iron phosphate composite material, which includes lithium iron phosphate, a highly conductive carbon coating, and a nanocomposite. The positive electrode material is located in the positive electrode region 2 inside Battery 1; The negative electrode material used in Battery 1 is a silicon-based composite material, which includes nanosilicon and graphite, or a composite of silicon particles and a conductive polymer material. The negative electrode material is located in the negative electrode region 3 inside Battery 1.

[0023] The positive electrode material contains 30% to 60% of lithium iron phosphate, 10% to 30% of the highly conductive carbon coating, and 10% to 30% of the nanocomposite. The nanocomposite is perovskite; The negative electrode material contains 70% to 90% of nanosilicon and 10% to 30% of graphite, or a composite of silicon particles and 10% to 15% of the conductive polymer material.

[0024] Specifically, by optimizing the electrolyte formulation and material structure, the present invention significantly improves the charging efficiency and energy density of the battery. First, by using a mixture of a modified lithium salt and a highly conductive solvent (such as a mixture of lithium hexafluorophosphate and ethylene carbonate), the internal resistance of the battery is reduced, and the ionic conductivity of the electrolyte is improved, thereby accelerating the charging speed of the battery. In addition, the negative electrode material adopts a structure of composite nanosilicon and graphite, which not only improves the specific capacity of the battery but also effectively solves the problem of volume expansion of silicon materials during charge and discharge, maintaining the cycle stability of the battery. The positive electrode material adopts an improved lithium iron phosphate composite material. By introducing highly conductive materials such as perovskite, the energy density of the battery is enhanced, and at the same time, the thermal stability and overall performance of the battery are improved. Overall, the integration of these innovative technologies improves the comprehensive performance of the battery in terms of fast charging and high-energy storage, and is particularly suitable for application scenarios that require high power and long-term use, such as electric vehicles and energy storage systems.

[0025] The electrolyte used in Battery 1 is an organic solvent solution containing a lithium salt. The lithium salt is lithium hexafluorophosphate, lithium tetrafluoroborate, or lithium trifluoromethanesulfonate, and the concentration of the lithium salt is 1.0 M to 1.5 M; The organic solvent of the electrolyte is a mixture of dimethyl carbonate, ethylene carbonate, and propylene carbonate. The mass ratio of each component in the mixture is 40% to 60% of ethylene carbonate, 30% to 50% of dimethyl carbonate, and 10% to 20% of propylene carbonate.

[0026] Specifically, by selecting different lithium salts such as lithium hexafluorophosphate and lithium tetrafluoroborate, the electrolyte of this embodiment can maintain a concentration in the range of 1.0 M to 1.5 M, providing stable battery performance within a wide operating temperature range. After optimizing the mixing ratio of the organic solvents in the electrolyte, the internal resistance can be effectively reduced, the ion migration speed can be increased, and the stable operation of the battery during high-current charging can be ensured. In addition, through this specific electrolyte formulation, the volatility and corrosiveness of the electrolyte can be reduced, improving the service life and safety of the battery.

[0027] The electrolyte in Battery 1 also contains 10% to 15% of nanoparticles or highly conductive polymer materials. The nanoparticles are alumina, titanium oxide, or silicon dioxide, and the highly conductive polymer materials are polyaniline or polypyrrole.

[0028] Specifically, the addition of nanoparticles and highly conductive polymer materials greatly enhances the conductivity of the electrolyte, which plays an important role in improving the charge and discharge efficiency of the battery. By introducing these highly conductive materials, the internal resistance of the battery can be significantly reduced, and the power density and charging rate of the battery can be increased. Especially during rapid charging, the conductivity of the electrolyte is improved, which can effectively reduce the polarization phenomenon of the electrolyte in the battery, prevent overheating, and optimize the overall performance of the battery.

[0029] The positive electrode material 2 and the negative electrode material 3 in Battery 1 are connected through the electrolyte and the separator. The separator is a polyolefin-based material with permeability. The porosity of the separator is 40% to 60%, and the thickness is 20 μm to 30 μm.

[0030] Specifically, by using a polyolefin-based material as the separator and controlling its porosity and thickness, the internal resistance of the battery can be reduced while ensuring good ionic conductivity. The high porosity ensures the rapid penetration of the electrolyte, improving the charging efficiency and the operating stability of the battery. The appropriate membrane thickness helps to avoid short-circuiting of the battery and also improves the mechanical strength of the separator, preventing damage to the battery during use.

[0031] The conductive additive used in Battery 1 is graphene, carbon nanotubes, or a composite material of graphene and carbon nanotubes. The mass ratio of the composite material is 2% to 10% of the negative electrode material.

[0032] Specifically, the use of highly conductive additives such as graphene and carbon nanotubes can significantly improve the conductivity of the negative electrode material of the battery and increase the electron migration rate during charging and discharging. Through reasonable ratio control, these conductive materials can enhance the cycle stability of the negative electrode, prevent capacity decay caused by polarization effects during long-term use of the battery, thereby extending the service life of the battery and improving the overall efficiency of the battery.

[0033] The battery 1 uses an electrolyte with high conductivity and low internal resistance. The internal resistance of the electrolyte is less than 50 mΩ at 20°C and can maintain low-temperature stability when the charging current reaches 1C.

[0034] Specifically, the electrolyte with low internal resistance can significantly reduce the energy loss inside the battery and ensure stability during high-current charging. This low-internal-resistance electrolyte helps the battery maintain a lower heat generation during rapid charging, reducing performance degradation and shortened lifespan caused by excessive battery temperature, and improving the efficiency and reliability of the battery.

[0035] The thickness of the electrolyte layer between the positive electrode region 2 and the negative electrode region 3 of the battery 1 is 10 μm to 20 μm and has ionic conductivity, and the internal resistance of the battery 1 is less than 20 mΩ.

[0036] Specifically, the optimization of the thickness and conductivity of the electrolyte layer helps improve the charging efficiency of the battery. A thinner electrolyte layer can reduce the internal resistance of the battery, while higher ionic conductivity ensures that the battery can operate stably during rapid charging, avoiding energy loss and improving the charging efficiency and overall performance of the battery.

[0037] Please refer to the appendix Figure 6 , a preparation method of a sealed valve-regulated power battery with high energy and fast charging efficiency, comprising the following steps: Step 1, prepare the positive electrode material and the negative electrode material Preparation of the positive electrode material: Select lithium iron phosphate as the base material and modify it by doping vanadium, molybdenum or chromium elements, with a doping ratio of 0.5% to 5%, and the particle diameter of the positive electrode material is 200 nm to 300 nm; Preparation of the negative electrode material: Use a silicon-based composite material as the negative electrode material, which is composed of 90% to 95% of nano-silicon particles and 5% to 10% of graphite, and the average diameter of the silicon particles is 100 nm; Step 2, surface modification of the positive and negative electrode materials Modify the positive electrode material by high-temperature nitridation method to coat a layer of high-conductivity carbon material on its surface; For the silicon-based composite negative electrode material, coat a silicon nitride layer on its surface by chemical vapor deposition method, and the thickness of the silicon nitride is 30 nm to 50 nm; Step 3, prepare the electrolyte The electrolyte is composed of lithium hexafluorophosphate, lithium tetrafluoroborate or lithium trifluoromethanesulfonate, the lithium salt concentration is 1.0 M to 1.5 M, select a mixed solution of dimethyl carbonate and ethylene carbonate as the solvent, and the solvent ratio is 40% to 60% of EC and 40% to 60% of DMC; at the same time, add 1% to 2% of ionic conductive additives; Step 4, prepare the separator A separator is prepared using polyolefin materials. Polypropylene nanofibers are combined with a polyethylene membrane by electrospinning technology, with a porosity of 50% to 70% and a thickness of 15 μm to 25 μm; Step 5: Combine the positive and negative electrode materials with the electrolyte The positive and negative electrode materials are connected through the electrolyte and the separator, and a stacked structure design is adopted to maximize the electrode area of the positive and negative electrodes; Step 6: Assemble the battery cell The positive and negative electrodes, the separator, the electrolyte and the battery management BMS system are combined to form a battery cell, and the battery housing is sealed with an aluminum alloy material.

[0038] The treatment temperature in Step 2 is 700 °C to 800 °C, and the treatment time is 4 to 6 hours.

[0039] Specifically, this method significantly improves the charging efficiency, stability, safety and service life of the battery through innovative improvements to the positive and negative electrode materials, electrolyte formula and separator material of the battery. The positive electrode material improves the electronic conductivity and thermal stability by doping elements such as vanadium and molybdenum and surface coating with highly conductive carbon materials; the negative electrode material uses a silicon-based composite material with a surface coating of silicon nitride to solve the silicon expansion problem and enhance the cycle stability. Ion-conductive additives are added to the electrolyte to improve the conductivity of the battery during rapid charging. The highly permeable separator using electrospinning technology enhances the ion permeability, reduces the battery internal resistance and extends the battery life.

[0040] The following is a detailed description of all the materials mentioned in the text, including their characteristics and applications: 1. Lithium iron phosphate (LiFePO4) Characteristics: Lithium iron phosphate is a commonly used cathode material for lithium batteries, with high thermal stability, chemical stability and safety. It has a long service life and high energy density, but compared with other lithium battery cathode materials, its power density is lower.

[0041] Applications: It is used in high-energy density batteries and is widely used in fields such as electric vehicles and energy storage systems.

[0042] 2. Sodium titanate (Na2Ti6O13) Characteristics: Sodium titanate is a sodium titanate compound and is commonly used in battery materials. It has good application prospects in enhancing the conductivity of the cathode material.

[0043] Applications: As a highly conductive material, sodium titanate is added to lithium iron phosphate to improve its conductivity and enhance the charge and discharge performance of the battery.

[0044] 3. Silicon (Si) Properties: Silicon is a commonly used material in anode materials, with a relatively high theoretical specific capacity. However, it has a volume expansion problem during charge and discharge processes, which limits its wide application.

[0045] Applications: In high-energy density batteries, silicon is often combined with graphite or other conductive materials to improve the specific capacity and cycle stability of the battery.

[0046] 4. Graphite (C) Properties: Graphite is a material with good electrical conductivity, chemical stability, and a relatively low expansion coefficient. It is one of the most commonly used anode materials for lithium-ion batteries. Its specific capacity is relatively low, but it can better withstand volume changes during charge and discharge.

[0047] Applications: Widely used as an anode material in lithium-ion batteries.

[0048] 5. Polyaniline (PANI) Properties: Polyaniline is a conductive polymer material with good electrical conductivity, environmental stability, and a long service life. It also has certain adjustable properties, and its conductivity can be changed through doping and reduction processes.

[0049] Applications: As a conductive additive in batteries to enhance the electrical conductivity of the electrolyte or anode material.

[0050] 6. Polypyrrole (PPy) Properties: Polypyrrole is another common conductive polymer material with excellent electrical conductivity and chemical stability. It is widely used in electrochemical storage devices.

[0051] Applications: As a conductive additive or used in batteries to improve conductivity and stability.

[0052] 7. Graphene Properties: Graphene is a two-dimensional material composed of a single layer of carbon atoms, with excellent electrical conductivity, thermal conductivity, and mechanical strength. As a conductive material in batteries, it can significantly improve the charging rate and cycle life of the battery.

[0053] Applications: As a conductive additive in anode materials, or combined with other materials to enhance the electrical conductivity and mechanical stability of the battery.

[0054] 8. Carbon nanotubes (CNTs) Properties: Carbon nanotubes have extremely high electron conductivity and mechanical strength, and at the same time have a large specific surface area, making them suitable for use in batteries to improve conductivity and thermal conductivity.

[0055] Applications: Used as a conductive additive in combination with anode materials to help improve the charging performance and cycle life of the battery.

[0056] 9. Lithium hexafluorophosphate (LiPF6) Properties: Lithium hexafluorophosphate is a commonly used lithium salt for lithium battery electrolytes, with high ionic conductivity. Its role in the battery is to provide a conduction path for lithium ions.

[0057] Applications: As the main lithium salt in battery electrolytes, it is widely used in lithium-ion batteries.

[0058] 10. Lithium tetrafluoroborate (LiBF4) Properties: Lithium tetrafluoroborate is another commonly used lithium salt, with good thermal stability and low corrosiveness, suitable for battery applications under high-temperature conditions.

[0059] Applications: As a lithium salt in the electrolyte, it improves the thermal stability and safety of the battery.

[0060] 11. Lithium trifluoromethanesulfonate (LiTFSI) Properties: Lithium trifluoromethanesulfonate is a new type of lithium salt, with high solubility and strong conductivity, widely used in applications that require high-conductivity electrolytes.

[0061] Applications: Used as a lithium salt in the electrolyte, it can improve the charge and discharge performance of the battery in high-power applications.

[0062] 12. Aluminum oxide (Al2O3) Properties: Aluminum oxide is a common ceramic material, with excellent thermal stability and low conductivity. In the battery, aluminum oxide is commonly used as an additive in the electrolyte to enhance the ionic conductivity and thermal stability of the electrolyte.

[0063] Applications: Used to improve the safety and stability of the battery.

[0064] 13. Titanium dioxide (TiO2) Properties: Titanium dioxide has good chemical stability and a high specific surface area, and is commonly used in the negative electrode material of the battery to improve its conductivity.

[0065] Applications: As an additive, it combines with the electrolyte or the negative electrode material to improve the charging rate and cycle performance of the battery.

[0066] 14. Silicon dioxide (SiO2) Properties: Silicon dioxide is a common oxide, with high conductivity and good chemical stability. It can enhance the conductivity of the battery's negative electrode material.

[0067] Applications: In the battery, it is used as a conductive additive or compounded with other materials.

[0068] 15. Polyolefin-based materials (such as polyethylene, polypropylene) Features: Polyolefin-based materials such as polyethylene and polypropylene have good mechanical strength, chemical stability, and high electrolyte permeability, and are widely used in battery separator materials.

[0069] Applications: Used as battery separators, they have high ionic conductivity and strong mechanical strength, ensuring the safety and stability of batteries during operation.

[0070] 16. Polyester materials (such as polyethylene terephthalate PET) Features: Polyester materials have good mechanical strength and low electrolyte absorption, which can effectively reduce the internal resistance of batteries and improve their stability.

[0071] Applications: As battery separator materials, they are used in batteries to play the role of electrolyte isolation and ion conduction.

[0072] The innovative use of these materials in battery technology, especially the addition of composite materials, can significantly improve the conductivity, thermal stability, cycle life and other characteristics of batteries, ensuring the safety and efficiency of batteries during high-power charging and use.

[0073] Experimental data and effect verification Experiment 1: Battery charging efficiency test Experimental purpose: To verify the influence of the improvements in optimizing the electrolyte and anode material in the present invention on the charging efficiency.

[0074] Experimental method: Select three groups of batteries for comparative experiments: Group 1: Traditional lithium iron phosphate battery, using a standard electrolyte.

[0075] Group 2: Using the lithium iron phosphate composite material of the present invention and optimizing the electrolyte formula.

[0076] Group 3: Using the nano-silicon composite anode material and high-conductivity electrolyte of the present invention.

[0077] At a constant ambient temperature (25°C), charge the three groups of batteries at 1C respectively, and record the charging time and the final charging capacity.

[0078] Results: The charging time of Group 1 is 120 minutes, and the charging efficiency is 85%.

[0079] The charging time of Group 2 is 95 minutes, and the charging efficiency is 91%.

[0080] The charging time of Group 3 is 75 minutes, and the charging efficiency is 96%.

[0081] Data analysis: The experimental results show that using the optimized electrolyte and anode material combination of the present invention can significantly improve the charging efficiency and charging speed of the battery and reduce the charging time.

[0082] Table 1: Experimental data table of charging efficiency

[0083] A charging rate of 1C was used during the charging process, and the battery was charged to 4.2V.

[0084] By comparing the charging time, charging amount, and charging efficiency of three different groups of batteries, it is proved that the battery of the present invention has a significant advantage in charging efficiency.

[0085] Explanation of table characters: Experimental group: Refers to the number or name of each group of experiments (such as Group 1, Group 2, Group 3) used to identify different experimental groups.

[0086] Battery type: Refers to the type or configuration of the battery used in each group of experiments (such as traditional lithium iron phosphate battery, optimized lithium iron phosphate composite battery, etc.).

[0087] Charging time (minutes): Refers to the time required to complete one charge, with the unit of minutes.

[0088] Charging amount (mAh): Refers to the amount of electricity stored in the battery during one charging process, with the unit of milliampere-hour (mAh).

[0089] Charging efficiency (%): Refers to the energy conversion efficiency of the battery during the charging process, calculated as the ratio of the charging amount to the electrical energy used, with the unit of percentage (%).

[0090] Experiment 2: Internal resistance test Experiment purpose: To test the change of the internal resistance of the battery under different material configurations.

[0091] Experiment method: Use an electrochemical impedance spectroscopy (EIS) analyzer to test the internal resistance of the battery.

[0092] Test the internal resistance of the battery at different charging states (0%, 50%, 100% SOC) respectively.

[0093] Results: Group 1 (traditional battery): The internal resistance is about 50 mΩ.

[0094] Group 2 (optimized battery of the present invention): The internal resistance is about 35 mΩ.

[0095] Group 3 (high-performance battery of the present invention): The internal resistance is about 25 mΩ.

[0096] Data analysis: The optimized batteries (especially Group 3) exhibit lower internal resistance during charging, demonstrating that the use of a new anode material and an improved electrolyte formulation effectively reduces the internal resistance, thereby enhancing the charging efficiency and battery stability.

[0097] Table 2: Internal Resistance Test Data Table

[0098] To measure the internal resistance of the battery under different charging states, an electrochemical impedance spectrometer (EIS) was used.

[0099] Experimental data show that the internal resistance of the batteries in the present invention is significantly lower than that of traditional batteries and optimized batteries, which helps to improve the charging efficiency and battery stability.

[0100] Explanation of table characters: Experimental group: Refers to the number or name of each experimental group (such as Group 1, Group 2, Group 3) used to identify different experimental groups.

[0101] Test conditions: Refers to the environmental or state conditions used during the experiment (such as temperature, charging state, etc.).

[0102] Battery internal resistance (mΩ): Refers to the resistance inside the battery, with the unit of milliohm (mΩ), used to measure the energy loss inside the battery.

[0103] State of charge (SOC): Refers to the charging state of the battery, usually expressed as the proportion of the remaining battery capacity. The higher the SOC, the more fully charged the battery is.

[0104] Details of the preparation method 1. Preparation of the cathode material Material composition: Lithium iron phosphate composite (LiFePO4), sodium titanate nanowires (Na2Ti6O13), conductive carbon coating.

[0105] Preparation process: Mix lithium iron phosphate and sodium titanate nanowires in a mass ratio of (1:1), add an appropriate amount of water and organic solvent, and perform ball milling.

[0106] Heat-treat the mixture at 300 °C for 3 hours to obtain a modified lithium iron phosphate composite.

[0107] Coat a layer of carbon coating on the surface of the composite material, and use the carbonization method to attach the conductive carbon material to the surface of the cathode.

[0108] Cool and dry the obtained cathode material to finally obtain a lithium iron phosphate composite with high conductivity.

[0109] Parameter settings: Ball milling time: 6 hours.

[0110] Heat treatment temperature: 300 °C.

[0111] Carbon coating thickness: about 50 nm.

[0112] 2. Preparation of the anode material Material composition: nano-silicon, graphite, polyaniline (PANI).

[0113] Preparation process: Mix nano-silicon and graphite in a mass ratio of (3:7), and add an appropriate amount of polyaniline (PANI) as a conductive agent.

[0114] Perform high-temperature reduction treatment on the mixture to obtain a silicon-based composite material.

[0115] Press the composite material into a battery anode sheet and perform drying treatment to ensure the stability of the material.

[0116] Parameter settings: High-temperature treatment temperature: 800 °C.

[0117] Dosage of polyaniline: 10% (relative to the mass of silicon material).

[0118] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A closed valve-regulated power battery with high energy and fast charging efficiency, comprising a battery (1), characterized in that: A positive electrode region (2) is disposed inside one side of the battery (1), and a negative electrode region (3) is disposed inside the other side of the battery (1); The positive electrode material used in the battery (1) is a lithium iron phosphate composite material, wherein the positive electrode material comprises lithium iron phosphate, a highly conductive carbon coating and a nanocomposite, and the positive electrode material is located in the positive electrode region (2) inside the battery (1); The negative electrode material used in the battery (1) is a silicon-based composite material, wherein the negative electrode material comprises nano-silicon and graphite, or comprises a composite of silicon particles and a conductive polymer material, and the negative electrode material is located in the negative electrode region (3) inside the battery (1).

2. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 1, characterized in that: The positive electrode material comprises 30% to 60% of lithium iron phosphate, 10% to 30% of a highly conductive carbon coating, and 10% to 30% of a nanocomposite, wherein the nanocomposite is sodium titanate; The negative electrode material contains 70% to 90% of nano silicon and 10% to 30% of graphite, or contains silicon particles and 10% to 15% of a conductive polymer material.

3. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 1, characterized in that: The electrolyte used in the battery (1) is an organic solvent solution containing a lithium salt, wherein the lithium salt is lithium hexafluorophosphate, lithium tetrafluoroborate or lithium trifluoromethanesulfonate, and the concentration of the lithium salt is 1.0M to 1.5M; The organic solvent of the electrolyte is a mixture of dimethyl carbonate, ethylene carbonate and propylene carbonate, and the mass ratio of each component in the mixture is 40% to 60% of ethylene carbonate, 30% to 50% of dimethyl carbonate and 10% to 20% of propylene carbonate.

4. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 3, characterized in that: The electrolyte in the battery (1) further contains 10% to 15% of nanoparticles or highly conductive polymer materials, wherein the nanoparticles are aluminum oxide, titanium oxide or silicon dioxide, and the highly conductive polymer material is polyaniline or polypyrrole.

5. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 1, characterized in that: The positive electrode material (2) and the negative electrode material (3) in the battery (1) are connected via an electrolyte and a separator. The separator is a polyolefin-based material and has permeability. The porosity of the separator is 40% to 60% and the thickness is 20 μm to 30 μm.

6. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 1, characterized in that: The conductive additive used in the battery (1) is graphene, carbon nanotubes or a composite material of graphene and carbon nanotubes, and the mass proportion of the composite material is 2% to 10% of the negative electrode material.

7. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 4, characterized in that: The battery (1) uses an electrolyte with high conductivity and low internal resistance, wherein the internal resistance of the electrolyte is less than 50 mΩ at 20°C and can maintain low temperature stability when the charging current reaches 1C.

8. The high energy and fast charging efficiency sealed valve-regulated power battery according to claim 4, characterized in that: The thickness of the electrolyte layer between the positive electrode region (2) and the negative electrode region (3) of the battery (1) is 10 μm to 20 μm and has ion conductivity. The internal resistance of the battery (1) is less than 20 mΩ.

9. A method for preparing a closed valve-regulated power battery with high energy and fast charging efficiency, characterized in that: The high energy and fast charging efficiency sealed valve-regulated power battery according to any one of claims 1 to 8 comprises the following steps: Step 1: Prepare positive and negative electrode materials Cathode material preparation: Lithium iron phosphate is selected as a substrate and modified by doping with vanadium, molybdenum or chromium elements, the doping ratio is 0.5% to 5%, and the particle diameter of the positive electrode material is 200nm to 300nm; Negative electrode material preparation: A silicon-based composite material is used as the negative electrode material, wherein the material is composed of 90% to 95% nano-silicon particles and 5% to 10% graphite, and the average diameter of the silicon particles is 100nm; Step 2: Surface modification of positive and negative electrode materials The positive electrode material is modified by a high-temperature nitridation method so that a layer of highly conductive carbon material is coated on its surface; A silicon nitride layer is coated on the surface of the silicon-based composite negative electrode material by a vapor deposition method, wherein the thickness of the silicon nitride is 30 nm to 50 nm; Step 3: Prepare electrolyte The electrolyte is composed of lithium hexafluorophosphate, lithium tetrafluoroborate or lithium trifluoromethanesulfonate, the lithium salt concentration is 1.0M to 1.5M, a mixed solution of dimethyl carbonate and ethylene carbonate is selected as the solvent, and the solvent ratio is 40% to 60% EC and 40% to 60% DMC; at the same time, 1% to 2% of ion conductive additives are added; Step 4: Prepare the diaphragm The diaphragm is prepared using polyolefin materials, and polypropylene nanofibers are combined with polyethylene membranes using electrospinning technology, with a porosity of 50% to 70% and a thickness of 15μm to 25μm; Step 5: Combine positive and negative electrode materials with electrolyte The positive electrode material and the negative electrode material are connected by electrolyte and separator, and a stacked structure design is adopted to maximize the positive and negative electrode areas; Step 6: Assemble the battery cells The positive and negative electrodes, separators, electrolytes and battery management BMS system are combined to form a battery cell, and the battery casing is sealed with aluminum alloy material.

10. The method for preparing a closed valve-regulated power battery with high energy and fast charging efficiency according to claim 9, characterized in that: The processing temperature in step 2 is 700° C. to 800° C., and the processing time is 4 to 6 hours.

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