Lithium cobalt oxide battery, its preparation method and electrical equipment

Abstract

The present application relates to the technical field of batteries, and discloses a lithium cobalt oxide battery, a preparation method thereof, and an electrical device. The method for preparing the lithium cobalt oxide battery includes: sequentially performing a charging process and an aging process on the formed lithium cobalt oxide battery; wherein, the power of the lithium cobalt oxide battery obtained by the charging process is 70% SOC to 100% SOC; the temperature of the aging process is 40°C to 60°C. The lithium cobalt oxide battery prepared by the method of the present application has strong stability, less capacity loss, and a long service life in a high-temperature and high-humidity environment. Moreover, the preparation method of the present application has strong operability, is simple and practical, has low cost, and is suitable for industrial production.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to lithium cobalt oxide batteries, their preparation methods, and electrical equipment using the same. Background Art

[0002] A battery is a device that converts chemical energy into electrical energy and is widely used in many fields such as mobile phones, digital cameras, laptops, electric bicycles, and electric vehicles. With the increase in application scenarios, the performance of the battery to be able to continuously operate in harsh environments becomes increasingly important. For example, in actual working conditions, a high-temperature and high-humidity storage environment is likely to cause the battery to experience capacity attenuation, thereby deteriorating the battery performance. Summary of the Invention

[0003] This application aims to solve at least one of the technical problems in the related art to some extent. For this reason, one objective of this application is to provide a lithium cobalt oxide battery, its preparation method, and electrical equipment using the same. The lithium cobalt oxide battery prepared by the method of this application has strong stability, less capacity loss, and a long service life in a high-temperature and high-humidity environment. Moreover, the method of this application has strong operability, is simple and practical, and has low cost, and is suitable for industrial production.

[0004] A first aspect of this application provides a method for preparing a lithium cobalt oxide battery. According to an embodiment of this application, the method includes: sequentially performing a charging process and an aging process on the formed lithium cobalt oxide battery;

[0005] wherein, the charge of the lithium cobalt oxide battery obtained by the charging process is 70% SOC to 100% SOC;

[0006] The temperature of the aging process is 40°C to 60°C.

[0007] According to the method of an embodiment of this application, after the formed lithium cobalt oxide battery undergoes a charging process to reach a high voltage state, an aging process is then performed. Under the aging process conditions of high temperature and high voltage, the film-forming additives in the electrolyte undergo oxidative decomposition, which helps to form a stable CEI film on the surface of the positive electrode sheet. The high-temperature environment promotes the rapid aging and formation of the CEI film, thereby enhancing the interfacial stability between the positive electrode sheet and the electrolyte, and reducing the situation where active lithium loses its activity due to being captured by the CEI film under high-temperature and high-humidity storage conditions. Thereby, the attenuation of the battery capacity is reduced, and the service life of the battery is extended.

[0008] According to an embodiment of this application, the above method for preparing a lithium cobalt oxide battery may further have the following additional technical features:

[0009] According to an embodiment of this application, the temperature of the aging process is 40°C to 50°C.

[0010] According to an embodiment of this application, the time of the aging process is 6 h to 48 h.

[0011] According to an embodiment of the present application, the time of the aging treatment is 20 h to 28 h.

[0012] According to an embodiment of the present application, the charging current of the charging treatment is 0.5C to 0.8 C.

[0013] According to an embodiment of the present application, the method further includes: discharging the lithium cobalt oxide battery after the aging treatment to 0% SOC to 70% SOC.

[0014] According to an embodiment of the present application, the method further includes: discharging the lithium cobalt oxide battery after the aging treatment to 40% SOC to 60% SOC;

[0015] And / or, the ambient temperature of the discharging is 20°C to 30°C.

[0016] According to an embodiment of the present application, before performing the charging treatment, the lithium cobalt oxide battery after formation is exhausted and the liquid injection port is sealed.

[0017] According to an embodiment of the present application, the lithium cobalt oxide battery includes an electrolyte, and the electrolyte includes a film-forming additive.

[0018] The second aspect of the present application provides a lithium cobalt oxide battery. According to an embodiment of the present application, the lithium cobalt oxide battery is obtained by the method for preparing a lithium cobalt oxide battery described in the first aspect of the present application.

[0019] The third aspect of the present application provides an electrical device. According to an embodiment of the present application, the electrical device includes the lithium cobalt oxide battery described in the second aspect of the present application.

[0020] The additional aspects and advantages of the present application will be partly given in the following description, partly will become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0022] Figure 1 Shows a schematic flow chart of a method for preparing a lithium cobalt oxide battery according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The embodiments of the present application will be described in detail below. The following described embodiments are exemplary and are only used to explain the present application, and should not be construed as a limitation to the present application.

[0024] It should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Further, in the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0025] In the ranges disclosed in the present application, the endpoints and any values of the ranges are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present application.

[0026] In the present application, the term "comprising" or "including" is an open expression, that is, it includes the content specified in the present application, but does not exclude other aspects of the content.

[0027] With the increase in application scenarios, the performance of the battery to continue to be used in harsh environments becomes increasingly important. For example, in actual working conditions, a high-temperature and high-humidity storage environment is likely to cause the battery to experience capacity attenuation, thereby deteriorating the battery performance. Specifically, when the battery is placed in a high-temperature and high-humidity environment, the following several types of chemical reactions mainly occur inside it: (1) Thermal decomposition reaction of the positive electrode material; (2) Oxidation reaction of the electrolyte at the positive electrode; (3) Reduction reaction of the electrolyte at the negative electrode; (4) Thermal decomposition reaction of the electrolyte; (5) Electrolytic water reaction.

[0028] In the present application, by subjecting the formed lithium cobalt oxide battery to aging treatment under high-pressure and high-temperature conditions, the electrode plate accelerates polarization expansion, the organic electrolyte fully infiltrates the electrode plate interface, and the film-forming additive components in the solution are preferentially oxidized and decomposed over the solvent, which can form a CEI film on the surface of the positive electrode plate. At the same time, the high-temperature environment promotes the rapid aging and formation of the CEI film, thereby enhancing the interfacial stability between the positive electrode plate and the electrolyte, and effectively reducing the situation where active lithium loses its activity due to being captured by the CEI film under high-temperature and high-humidity storage conditions. Thus, the attenuation of the battery capacity is reduced, and the service life of the battery is extended.

[0029] Based on this, in the first aspect of the present application, a method for preparing a lithium cobalt oxide battery is proposed. Figure 1 The schematic flow diagram of the method for preparing the battery according to the present application is shown, and the method includes: S100 charging process and S200 aging process, and each step will be described in detail below.

[0030] S100 charging process

[0031] In this step, the formed lithium cobalt oxide battery is subjected to a charging process. Thereby, the battery can be in a high-voltage state, facilitating the subsequent aging process to form a stable CEI film.

[0032] According to an embodiment of the present application, the charge of the lithium cobalt oxide battery obtained by the charging process is 70% SOC to 100% SOC. For example, it can be 70% SOC, 80% SOC, 85% SOC, 90% SOC, 95% SOC, 100% SOC, etc. Charging the battery to the above state of charge (SOC) can make the battery in a high-voltage state, increasing the degree of polarization expansion of the electrode material, making it easier for the electrolyte to fully infiltrate the surface of the electrode material, providing more reaction sites, and enabling the film-forming additive to be preferentially oxidized and decomposed over the solvent, and the product forms a stable CEI film on the surface of the high-voltage positive electrode sheet.

[0033] It should be noted that in the present application, the term "charging process" refers to a processing method that includes a charging step. During the charging process, a discharging step may also be included. Exemplarily, during the charging process, the formed lithium cobalt oxide battery can be directly charged to the target charge, or first charged to 100% SOC and then discharged to the target charge, with the discharging current being 0.4 C to 0.6 C, and the corresponding target charge is achieved by adjusting the discharging time.

[0034] According to an embodiment of the present application, the charging current of the charging process is 0.5 C to 0.8 C. For example, it can be 0.5 C, 0.6 C, 0.7 C, 0.8 C, etc. Thereby, both rapid charging can be achieved, and the loss of electrode sheet material and electrolyte and heat generation can be reduced.

[0035] According to an embodiment of the present application, the lithium cobalt oxide battery includes: an electrolyte, and the electrolyte includes a film-forming additive. During the charge and discharge process of the battery, the film-forming additive can undergo a chemical reaction on the electrode surface to form a protective solid electrolyte interface (SEI) or cathode electrolyte interface (CEI) film. This film can improve the interfacial stability between the electrode and the electrolyte, reduce the decomposition of the electrolyte and the irreversible loss of active lithium, thereby extending the cycle life of the battery, improving its performance and safety in extreme environments, reducing capacity attenuation, and ensuring the long-term stable operation of the battery.

[0036] The present application does not strictly limit the types of film-forming additives, which can be commonly used film-forming additives in the art. Exemplarily, the film-forming additives include at least one of succinonitrile, carbonate esters, ethylene carbonate, vinylene ethylene carbonate, vinyl carbonate, fluoro vinyl carbonate, vinyl ethyl carbonate, vinylene carbonate, ethyl acrylate, vinyl alkyl carbonate, 1,3-propane sultone, propylene carbonate sultone, diethylene glycol sulfate, dimethoxy sulfonyl ethane, vinyl sulfonic acid lactone, diphenyl disulfide, tetramethyl disulfide, vinylene carbonate sultone, and styrene sulfonic acid lactone. Thereby, it helps to form more stable CEI and SEI films. Among them, succinonitrile (SN) acts on the surface of the metal oxide to form a stable and low-impedance CEI film, inhibiting the direct contact between the electrolyte and the positive electrode.

[0037] According to an embodiment of the present application, the positive electrode tab includes a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes lithium cobaltate. The positive electrode current collector may include a metal foil or a composite positive electrode current collector. For example, the metal foil may be made of aluminum foil. The composite positive electrode current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. For example, the composite negative electrode current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0038] According to an embodiment of the present application, the positive electrode active material layer may further optionally include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0039] According to an embodiment of the present application, the positive electrode active material layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0040] According to an embodiment of the present application, the positive electrode tab can be prepared in the following manner: dispersing the above components for preparing the positive electrode tab, such as the positive electrode active material, the conductive agent, and the binder, in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the positive electrode current collector, and after processes such as drying and cold pressing, the positive electrode tab can be obtained.

[0041] According to an embodiment of the present application, the lithium cobalt oxide battery further includes a negative electrode plate, which includes a negative electrode active material layer and a negative electrode current collector, and the negative electrode active material layer is disposed on at least one surface of the negative electrode current collector.

[0042] According to an embodiment of the present application, the negative electrode active material layer includes at least one of graphite, artificial graphite, silicon-based material, and tin-based material.

[0043] According to an embodiment of the present application, the negative electrode active material layer includes mesocarbon microbeads. Mesocarbon microbeads (MCMB) are a kind of carbon-coated lithium metal oxide, usually a composite material composed of a mixture of LiCoO2 and graphite material, and this structure can provide better electrical conductivity and structural stability. In a high-temperature and high-humidity environment, the stability of this composite material is better.

[0044] According to an embodiment of the present application, the negative electrode active material layer may also optionally include a binder. The binder may include at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0045] According to an embodiment of the present application, the negative electrode active material layer may also optionally include a conductive agent. The conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0046] According to an embodiment of the present application, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil can be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc.).

[0047] According to an embodiment of the present application, the lithium cobalt oxide battery further includes a separator, and the separator is located between the positive electrode plate and the negative electrode plate. The present invention does not particularly limit the type of the separator, and any publicly known porous structure separator with good chemical stability and mechanical stability can be selected. According to an embodiment of the present application, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, or polyvinylidene fluoride.

[0048] According to an embodiment of the present application, the method for preparing the formed lithium cobalt oxide battery includes: installing a fixture on the outer surface of the battery cell after liquid injection, charging the battery cell with a constant current of 0.2C to 0.4C for 20 to 40 minutes; then charging with a constant current of 0.8C - 1C for 40 to 60 minutes. Thereby, it is beneficial to form a uniform and stable solid electrolyte interface (SEI) and cathode electrolyte interface (CEI) film.

[0049] According to an embodiment of the present application, before performing the charging process, the formed lithium cobalt oxide battery is exhausted and the liquid injection port is sealed. Compared with the closed formation, in the open formation method, after formation, the gas generated inside during the formation process, such as CO2, H2, etc., is released through exhaust, which helps to reduce the internal pressure of the battery and avoid battery swelling or rupture. After the formation is completed, exhaust and seal the liquid injection port, which is convenient for subsequent charging and aging processes.

[0050] S200 Aging process

[0051] In this step, the lithium cobalt oxide battery after the charging process is subjected to an aging process.

[0052] According to an embodiment of the present application, the temperature of the aging process is 40°C to 60°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, etc. Exemplarily, the temperature of the aging process is 40°C to 50°C. Thereby, under high temperature and high pressure conditions, the degree of polarization expansion of the electrode material increases, the electrolyte is more likely to fully infiltrate the surface of the electrode material, providing more reaction sites, and the film-forming additive can be preferentially oxidized and decomposed before the solvent, and the product forms a stable CEI film on the surface of the high-voltage cathode electrode. At the same time, the high-temperature environment promotes the rapid aging and formation of the CEI film, thereby enhancing the interface stability between the cathode electrode and the electrolyte. And it can reduce the chemical degradation and internal resistance of the electrode material and the electrolyte.

[0053] According to an embodiment of the present application, the time of the aging process is 6 h to 48 h, such as 6 h, 12 h, 18 h, 20h, 24 h, 28 h, 32 h, 36 h, 48 h, etc. Exemplarily, the time of the aging process is 20 h to 28 h. Thereby, it can not only form a stable CEI film, but also reduce the chemical degradation and internal resistance of the electrode material and the electrolyte.

[0054] According to an embodiment of the present application, the method for preparing a battery further includes: S300 Discharge treatment, specifically including discharging the lithium cobalt oxide battery after the aging treatment to 0% - 70%, such as 0% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, etc., and exemplarily being 40% SOC - 60% SOC. Exemplarily, the temperature of the discharge is 20°C - 30°C, and can be, for example, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C. Thereby, the battery can be placed in a relatively low state of charge (SOC), so as to reduce the attenuation of the battery capacity and extend the storage time of the battery.

[0055] The second aspect of the present application proposes a lithium cobalt oxide battery. According to an embodiment of the present application, the lithium cobalt oxide battery is obtained by the method for preparing a lithium cobalt oxide battery described in the first aspect of the present application. The lithium cobalt oxide battery of the present application has good storage performance in a high-temperature and high-humidity environment, is not prone to capacity reduction, and has a long service life. The features and advantages described above for the method for preparing a lithium cobalt oxide battery also apply to this battery, and will not be elaborated herein.

[0056] The third aspect of the present application proposes an electrical device. According to an embodiment of the present application, the electrical device includes the lithium cobalt oxide battery described in the second aspect of the present application. The features and advantages described above for the lithium cobalt oxide battery also apply to this electrical device, and will not be elaborated herein.

[0057] The battery cell, battery module, and battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device can include mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc., but is not limited thereto.

[0058] As an electrical device, the battery cell, battery module, or battery pack can be selected according to its usage requirements.

[0059] As an electrical device of an embodiment, it can be a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc. In order to meet the high-power and high-energy density requirements of the electrical device for the battery, a battery pack or a battery module can be used.

[0060] As another embodiment of the device, it can be a mobile phone, a tablet computer, a laptop computer, etc. This device usually requires being thin and light, and a battery cell can be used as the power source.

[0061] The solution of the present application will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those without specific techniques or conditions noted in the embodiments, the techniques or conditions described in the literature in this field or according to the product specifications are followed. For reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0062] Embodiment 1

[0063] 1. Using LiCoO2 as the cathode material, carbon nanotubes and acetylene black as conductive agents, and polyvinylidene fluoride as the binder, the cathode material, carbon nanotubes, acetylene black, and polyvinylidene fluoride are mixed evenly according to a mass ratio of 85:10:5:50, then coated on aluminum foil, and then placed in an oven at 120 °C for vacuum drying for 24 h, and then made into a cathode electrode sheet after pressing and slitting; using MCMB (mesophase carbon microspheres) as the anode and celgard2400 polypropylene porous membrane as the separator. The assembly of the battery cell is completed in a glove box filled with argon.

[0064] 2. The battery cell is installed in the outer packaging shell, and the electrolyte (the mass ratio of cyclic carbonate, linear carbonate, lithium tetrafluoroborate, succinonitrile, ethylene carbonate, and vinylene carbonate is 1:1:1:1:1:1) is injected, and the following formation treatment is carried out: Install a fixture on the outer surface of the battery cell after the injection of the electrolyte is completed, first charge the battery cell with a constant current of 0.3C for 30 min; then charge it with a constant current of 0.9C for 50 min.

[0065] 3. The battery obtained in the previous step is evacuated and the injection port is sealed. At this time, the battery voltage is 4.0V and the battery charge is 60% SOC.

[0066] 4. The battery obtained in the previous step is charged at 0.7C to 4.48V at room temperature (25 ± 3 °C) and cut off at 0.025C. At this time, the battery charge is 100% SOC.

[0067] 5. The battery obtained in the previous step is placed in an oven at 45 °C for aging for 24 h; then taken out.

[0068] 6. The battery obtained in the previous step is discharged to 3.90V at room temperature (25 ± 3 °C). At this time, the battery charge is 50% SOC, and a lithium-ion battery is obtained.

[0069] Embodiment 2

[0070] The difference from Embodiment 1 is that in step 4, it is charged at 0.7C to 4.48V and cut off at 0.025C. At this time, the battery cell is full at 100% SOC, and then discharged at 0.5C for 36 min. At this time, the battery charge is 70% SOC.

[0071] Example 3

[0072] The difference from Example 1 is that in Step 4, it is charged at 0.7C to 4.48V and cut off at 0.025C. At this time, the battery cell is at 100% full SOC, and then discharged at 0.5C for 24 minutes. At this time, the battery power is 80% SOC.

[0073] Example 4

[0074] The difference from Example 1 is that in Step 4, it is charged at 0.7C to 4.48V and cut off at 0.025C. At this time, the battery cell is at 100% full SOC, and then discharged at 0.5C for 12 minutes. At this time, the battery power is 90% SOC.

[0075] Example 5

[0076] The difference from Example 1 is that in Step 5, the aging treatment time is 6 h.

[0077] Example 6

[0078] The difference from Example 1 is that in Step 5, the aging treatment time is 20 h.

[0079] Example 7

[0080] The difference from Example 1 is that in Step 5, the aging treatment time is 28 h.

[0081] Example 8

[0082] The difference from Example 1 is that in Step 5, the aging treatment time is 48 h.

[0083] Example 9

[0084] The difference from Example 1 is that Step 6 is not included.

[0085] Example 10

[0086] The difference from Example 1 is that in Step 6, the battery obtained in the previous step is discharged to 3.97V at room temperature. At this time, the battery power is 40% SOC.

[0087] Example 11

[0088] The difference from Example 1 is that in Step 6, the battery obtained in the previous step is discharged to 3.81V at room temperature. At this time, the battery power is 60% SOC.

[0089] Example 12

[0090] The difference from Example 1 is that in Step 6, the battery obtained in the previous step is discharged to 3.0V at room temperature. At this time, the battery power is 0% SOC.

[0091] Example 13

[0092] The difference from Example 1 is that in Step 6, the battery obtained in the previous step is discharged to 3.76V at room temperature, and at this time the battery charge is 70% SOC.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that Steps 4-6 are not included.

[0095] Comparative Example 2

[0096] The difference from Example 1 is that Step 4 is not included, and the lithium cobalt oxide battery after being processed in Step 3 is directly subjected to Step 5.

[0097] Comparative Example 3

[0098] The difference from Example 1 is that Step 5 is not included, and the lithium cobalt oxide battery after being processed in Step 4 is directly subjected to Step 6.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that in Step 5, the temperature of the aging treatment is 30°C.

[0101] Comparative Example 5

[0102] The difference from Example 1 is that in Step 5, the temperature of the aging treatment is 70°C.

[0103] Comparative Example 6

[0104] The difference from Example 1 is that in Step 4, it is charged to 4.48V at 0.7C and cut off at 0.025C. At this time, the battery cell is full at 100% SOC, and then discharged at 0.5C for 48 minutes. At this time, the battery charge is 60% SOC.

[0105] Comparative Example 7

[0106] The difference from Example 1 is that LiCoO2 is replaced with lithium iron phosphate.

[0107] Test Example

[0108] The lithium-ion batteries prepared in Examples 1-13 and Comparative Examples 1-7 are respectively subjected to high-temperature and high-humidity storage performance tests. The specific steps are as follows:

[0109] Under the condition of 25 ± 3°C, charge the lithium-ion battery at 0.7C to 4.48V, cut off at 0.025C until fully charged. Cycle 2 times under this condition, and take the discharge capacity of the second cycle as the initial capacity. After the fully charged battery is left open-circuited at (60 ± 2)°C and 90% humidity for 7 days, then left open-circuited at room temperature for 2 hours, and discharged at a constant current of 0.5C to 3.0V, which is recorded as the remaining capacity; then charge at 0.7C to 4.48V, cut off at 0.025C / discharge at a constant current of 0.5C to 3.0V, cycle 3 times, and the highest capacity is recorded as the recovered capacity. Capacity remaining rate (%) = remaining capacity / initial capacity, capacity recovery rate (%) = recovered capacity / initial capacity.

[0110] The results are shown in Table 1. Compared with Comparative Examples 1-7, the overall performance of the lithium-ion batteries prepared in Examples 1-13 is more excellent. After formation, the lithium cobalt oxide battery is charged to a high voltage state, and then aged. Under the conditions of high temperature (40°C - 60°C) and high voltage (70% SOC - 100% SOC), the film-forming additives in the electrolyte are oxidized and decomposed, which helps to form a stable CEI film on the surface of the positive electrode plate. The high-temperature environment promotes the rapid aging and formation of the CEI film, thereby enhancing the interfacial stability between the positive electrode plate and the electrolyte, and reducing the loss of active lithium due to being trapped by the CEI film under high-temperature and high-humidity storage conditions, reducing the attenuation of the battery capacity. Therefore, the lithium-ion battery has strong stability, less capacity loss, and high capacity remaining rate and recovery rate in a high-temperature and high-humidity storage environment.

[0111] It can be seen from Comparative Example 7 that the method for preparing the battery in this application is not applicable to lithium iron phosphate, which has poor stability, more capacity loss, poor capacity recovery effect, and poor overall performance in a high-temperature and high-humidity storage environment.

[0112] Table 1

[0113]

[0114] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for preparing a lithium cobalt oxide battery, characterized in that: include: The formed lithium cobalt oxide battery is sequentially subjected to charging treatment and aging treatment; Discharging the aged lithium cobalt oxide battery to 40% SOC-60% SOC; Wherein, the electric capacity of the lithium cobalt oxide battery obtained by the charging process is 70% SOC~100% SOC; The temperature of the aging treatment is 40°C to 60°C; The aging treatment time is 6 h to 48 h; The lithium cobalt oxide battery comprises a negative electrode plate, the negative electrode plate comprises a negative electrode active material layer, and the negative electrode active material layer comprises mesophase carbon microspheres.

2. The method according to claim 1, characterized in that The charging current of the charging process is 0.5C~0.8C.

3. The method according to claim 1 or 2, characterized in that: The temperature of the aging treatment is 40°C to 50°C.

4. The method according to claim 1 or 2, characterized in that The aging treatment time is 20 h to 28 h.

5. The method according to claim 1, characterized in that The ambient temperature of the discharge is 20°C to 30°C.

6. The method according to claim 1, characterized in that Before the charging process is performed, the formed lithium cobalt oxide battery is vented and the liquid injection port is sealed.

7. The method according to claim 1, characterized in that The lithium cobalt oxide battery includes an electrolyte, and the electrolyte includes a film-forming additive.

8. A lithium cobalt oxide battery, characterized in that: The lithium cobalt oxide battery is obtained by the method for preparing a lithium cobalt oxide battery according to any one of claims 1 to 7.

9. An electrical device, characterized in that: Including the lithium cobalt oxide battery as described in claim 8.

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