WO2022027223A1 - 电子装置、用于电化学装置的充电方法、终端和存储介质 - Google Patents

电子装置、用于电化学装置的充电方法、终端和存储介质 Download PDF

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WO2022027223A1
WO2022027223A1 PCT/CN2020/106782 CN2020106782W WO2022027223A1 WO 2022027223 A1 WO2022027223 A1 WO 2022027223A1 CN 2020106782 W CN2020106782 W CN 2020106782W WO 2022027223 A1 WO2022027223 A1 WO 2022027223A1
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charging
electrochemical device
soc
lithium
electronic device
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PCT/CN2020/106782
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English (en)
French (fr)
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陈茂华
魏红梅
谢远森
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宁德新能源科技有限公司
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Priority to CN202210355202.2A priority Critical patent/CN114497781B/zh
Priority to CN202080004737.4A priority patent/CN112640185B/zh
Priority to JP2021516670A priority patent/JP7443350B2/ja
Priority to EP20936099.9A priority patent/EP3979392A4/en
Priority to PCT/CN2020/106782 priority patent/WO2022027223A1/zh
Publication of WO2022027223A1 publication Critical patent/WO2022027223A1/zh
Priority to US17/708,766 priority patent/US20220224141A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/40—Alloys based on alkali metals
    • H01M4/405—Alloys based on lithium
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
    • H02J7/0048—Detection of remaining charge capacity or state of charge [SOC]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/00714—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current
    • H02J7/00718—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery charging or discharging current in response to charge current gradient
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • H02J7/007184—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage in response to battery voltage gradient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of electronic technology, and in particular, to electronic devices, charging methods for electrochemical devices, terminals and storage media.
  • Lithium metal is the metal with the smallest relative atomic mass (6.94) and the lowest standard electrode potential (-3.045V) among all metal elements, and its theoretical gram capacity can reach 3860mAh/g. Therefore, using lithium metal as the negative electrode of an electrochemical device, in combination with some high-energy-density positive electrode materials, can greatly improve the energy density of the electrochemical device and the working voltage of the electrochemical device.
  • lithium metal deposits on the surface of the negative electrode. Due to the high chemical reactivity of lithium metal itself, it will react with the electrolyte during the deposition process to form a solid electrolyte interfacial film (SEI).
  • SEI solid electrolyte interfacial film
  • lithium dendrites As the lithium metal continues to be deposited, the negative electrode expands in volume, and the original SEI will rupture, resulting in uneven local electric field, resulting in the preferential deposition of lithium metal at these locations, and then the formation of lithium dendrites.
  • the formation of lithium dendrites will continue to consume the electrolyte, resulting in insufficient electrolyte in lithium metal batteries; on the other hand, during the process of delithiation, lithium dendrites easily lose electrical contact with the lithium metal of the host, resulting in the loss of active lithium. loss, and improve the impedance of lithium metal batteries. This will seriously affect the cycle performance of lithium metal batteries and cause severe cycle decay of lithium metal batteries.
  • the present application improves the high-rate charging performance of electrochemical devices (for example, lithium metal batteries) by optimizing the charging process, and can improve the cycle life of electrochemical devices under similar charging times.
  • electrochemical devices for example, lithium metal batteries
  • Embodiments of the present application provide an electronic device including an electrochemical device that satisfies the following characteristics: in a first stage of a charging process, a state of charge (SOC) of the electrochemical device is less than or equal to X, 70% ⁇ X ⁇ 100%, wherein the average charging current is A when the state of charge (SOC) of the electrochemical device is less than or equal to 40%, and the state of charge (SOC) of the electrochemical device is A The average charging current between 40% and X is B, and A ⁇ B.
  • SOC state of charge
  • the negative electrode of the electrochemical device contains lithium metal or an alloy of lithium metal.
  • the alloy of lithium metal further includes metal M, and M includes Na, Al, Mg, Si, K, Ga, Fe, Zn, Ag, Y, Sb, In, At least one of Sn or B.
  • the charging process further includes a second stage when the state of charge (SOC) of the electrochemical device is between Y ⁇ 100%, wherein X ⁇ Y ⁇ 100%, the first stage The second stage adopts the constant voltage charging method.
  • SOC state of charge
  • the charging current is increased in steps, the number of steps n ⁇ 2, and the charging time of each step is the same or different.
  • the manner of increasing the steps includes that the charging time of each step is the same or the charging capacity of each step is the same.
  • the charging current is in a continuously increasing manner, or in a periodic manner in which the charging current is first continuously increased and then kept constant.
  • Embodiments of the present application also provide a charging method for an electrochemical device, comprising: in a first stage of a charging process, the state of charge (SOC) of the electrochemical device is less than or equal to X, and 70% ⁇ X ⁇ 100%, the average charging current when the state of charge (SOC) of the electrochemical device is less than or equal to 40% is set to A, and the state of charge (SOC) of the electrochemical device is set to be between 40% and X
  • the average charging current during the period is set to B, A ⁇ B.
  • An embodiment of the present application further provides a terminal, including: at least one memory and at least one processor; wherein the at least one memory is used to store program codes, and the at least one processor is used to call the at least one memory
  • the stored program code executes the charging method described above.
  • Embodiments of the present application further provide a storage medium, where the storage medium is used to store program codes, and the program codes are used to execute the above charging method.
  • the cycle performance of the electrochemical device can be improved under the condition that only a short charging time (eg, fast charging) is required. That is, the electronic device of the present application can improve the cycle life of the corresponding electrochemical device under the condition that the charging time is similar to that required by the current fast charging.
  • a short charging time eg, fast charging
  • FIG. 1 shows a schematic diagram of an electronic device according to an embodiment of the present application.
  • FIG. 7 shows a schematic flowchart of a charging method according to an embodiment of the present application.
  • lithium metal batteries are still faced with the following problems to be solved: 1) Li metal itself is highly reactive, especially the newly formed lithium metal, which is very prone to a series of side reactions with the existing organic small molecule electrolyte system. , causing the lithium metal and the electrolyte to be consumed at the same time, the cycle coulomb efficiency is generally less than 99.5%, and the cycle coulomb efficiency in the traditional liquid electrolyte system is generally less than 90%, which is much lower than the general graphite anode system (greater than 99.9%); 2 ) During the charging process of lithium metal batteries, lithium deposits on the surface of the negative electrode.
  • the deposition rate of some sites will be too fast during the deposition process, and then a sharp dendrite structure will be formed; the existence of lithium dendrites will lead to a large deposition density. If the energy density is reduced, the energy density will decrease.
  • the separator may be pierced to form a short circuit, causing safety problems;
  • the thickness of the negative electrode plate will undergo severe expansion-shrinkage, and the expansion and The thickness of the shrinkage is related to the amount of active material per unit area of the negative electrode and the specific capacity of the active material, as well as the density of lithium deposition and the volume of side reaction products; according to the current general design of commercial lithium-ion batteries, the single-sided lithium metal negative electrode is fully charged The thickness change relative to full discharge will reach 8 ⁇ m ⁇ 100 ⁇ m; this will cause the interface between the negative pole piece and the less flexible inorganic protective coating to peel off and lose the protective effect; 4)
  • the charging rate is low and the charging rate is large In this case, the deposition of lithium metal is more prone to non-uniformity, aggravating the growth of lithium dendrites, and the size of lithium metal particles will become smaller, increasing the area of side reactions with the electrolyte, resulting in
  • the following methods are mainly used: 1) The method of early protection, that is, in the electrical Before the chemical device is assembled, one or more stable protective layer structures are deposited on the surface of the lithium metal negative electrode by physical or chemical methods. This protective layer is stable to lithium, can conduct lithium ions, and isolate the electrolyte and lithium metal directly.
  • the electrochemical device of the present application includes, but is not limited to, a general lithium metal battery, that is, a battery in which the negative electrode is formed of lithium metal or an alloy of lithium metal, and also includes the negative electrode caused by the deposition of lithium on the surface of the negative electrode during the charging process.
  • Lithium-ion batteries containing lithium metal or an alloy of lithium metal which become lithium metal batteries during charging).
  • the negative electrode is made of traditional graphite, silicon-based materials, etc., but the CB is far less than 1.
  • CB (M'*N'*O')/(M*N*O) ⁇ 1.4, where M represents the mass ratio of the positive active material to the positive active material layer, N represents the gram capacity of the positive active material, The unit is mAh/g, O represents the mass per unit area of the positive electrode active material layer, the unit is mg/cm 2 , M' represents the mass ratio of the negative electrode active material to the negative electrode active material layer, N' represents the gram capacity of the negative electrode active material, The unit is mAh/g, and O' represents the mass per unit area of the negative electrode active material layer, and the unit is mg/cm 2 .
  • an embodiment of the present application provides an electronic device 1 including an electrochemical device 2 .
  • the electronic device 1 of the embodiment of the present application is not particularly limited, and it may be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
  • the electrochemical devices of the present application include, but are not limited to, lithium metal batteries or lithium ion batteries that become lithium metal batteries during charging.
  • the electrochemical device 2 of the present application satisfies the following characteristics: in the first stage of the charging process, the state of charge (SOC) of the electrochemical device is less than or equal to X, 70% ⁇ X ⁇ 100%, wherein, The average charging current is A when the state of charge (SOC) of the electrochemical device is less than or equal to 40%, and the average charging current is B when the state of charge (SOC) of the electrochemical device is 40% to X, and A ⁇ B.
  • the cycle life of the electrochemical device can be improved under the condition of satisfying the similar charging time for high-rate charging.
  • the negative electrode of the electrochemical device contains lithium metal or an alloy of lithium metal.
  • the anode of the electrochemical device may itself be lithium metal or an alloy of lithium metal, ie, the anode of the electrochemical device is formed of lithium metal or an alloy of lithium metal.
  • the negative electrode of the electrochemical device may be conventional graphite or the like, but as the charging process proceeds, lithium metal is precipitated on the negative electrode, so that the surface of the negative electrode is lithium metal or an alloy of lithium metal, which becomes a lithium metal battery .
  • metal M in addition to lithium, metal M may be included, and M includes Na, Al, Mg, Si, K, Ga, Fe, Zn, Ag, Y, Sb, In At least one of , Sn or B.
  • the charging process further includes a second stage when the state of charge (SOC) of the electrochemical device is between Y ⁇ 100%, wherein X ⁇ Y ⁇ 100%, and the second stage adopts a constant voltage charging method. Since the resistance of the electrochemical device is relatively large when it is almost fully charged, from the perspective of safety and preventing overcharging, a constant voltage charging method can be used.
  • SOC state of charge
  • the charging current is increased in steps, the number of steps n ⁇ 2, and the charging time of each step is the same or different.
  • FIG. 3 and FIG. 4 show schematic charging modes of current changes over time in Example 1 and Example 8, respectively.
  • the step-by-step manner includes the same charging time for each step or the same charging capacity for each step.
  • the charging current in the first stage of the charging process, is in a continuously increasing manner, or in a periodic manner in which the charging current is continuously increased and then kept constant.
  • Figures 5 and 6 show these two ways, respectively.
  • an embodiment of the present application further provides a charging method for an electrochemical device, which includes step S101 : in the first stage of the charging process, the state of charge (SOC) of the electrochemical device is less than equal to X, 70% ⁇ X ⁇ 100%, set the average charging current when the state of charge (SOC) of the electrochemical device is less than or equal to 40% as A, and set the state of charge (SOC) of the electrochemical device to be 40% ⁇
  • the average charging current between X is set to B, A ⁇ B.
  • the negative electrode of the electrochemical device contains lithium metal or an alloy of lithium metal.
  • the charging method of the present application As the charging progresses, the SOC increases.
  • the charging current in the later stage is greater than the charging current in the earlier stage, which can avoid the growth of lithium dendrites caused by excessive current in the earlier stage and The problem of increased side reactions improves the cycle performance of the electrochemical device.
  • due to the large current in the later stage of the first stage it also meets the requirements of high-rate charging and saves charging time. Therefore, by increasing the charging current in the later stage, the cycle life of the electrochemical device can be improved under a similar charging time.
  • the charging method of the present application is particularly suitable for electrochemical devices such as lithium metal batteries.
  • the present disclosure also provides a terminal, comprising: at least one memory and at least one processor; wherein the memory is used for storing program codes, and the processor is used for calling the program codes stored in the memory to perform the above charging method.
  • the terminals in the embodiments of the present disclosure may include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, assisted bicycles, bicycles, Lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household storage batteries and lithium-ion capacitors, etc.
  • the present disclosure also provides a computer storage medium, where the computer storage medium stores program codes, and the program codes are used to execute the above charging method.
  • the computer storage medium of the present application may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the above two.
  • the computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, or a combination of any of the above.
  • Computer readable storage media may include, but are not limited to, electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read only memory (ROM), erasable Programmable read only memory (EPROM or flash memory), fiber optics, portable compact disk read only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.
  • RAM random access memory
  • ROM read only memory
  • EPROM or flash memory erasable Programmable read only memory
  • CD-ROM compact disk read only memory
  • optical storage devices magnetic storage devices, or any suitable combination of the foregoing.
  • the preparation method of the lithium metal battery or the lithium ion battery converted into a lithium metal battery in the charging process of the present application is not limited, and can be prepared by a known method.
  • the positive electrode, separator, and negative electrode are sequentially wound or stacked to form electrode parts, and then packed into, for example, aluminum-plastic film for packaging, injected with electrolyte, formed, and packaged to form a lithium-ion battery or lithium ion battery.
  • Metal battery, wherein the negative electrode of lithium metal battery is usually lithium metal or lithium metal alloy.
  • the negative electrode current collector is copper foil with a thickness of 12 ⁇ m, and both sides are covered with lithium foil with a thickness of 50 ⁇ m.
  • the negative pole piece is cut into (40mm*60mm) specifications for use.
  • positive electrode sheet The positive active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 , the conductive agent conductive carbon black, and the binder polyvinylidene fluoride (PVDF) were dissolved in N- In the methyl pyrrolidone (NMP) solution, a positive electrode slurry with a solid content of 0.75 was prepared and stirred evenly. Using aluminum foil as the positive electrode current collector, coating the positive electrode slurry on the positive electrode current collector, drying at 90°C, cold pressing, and cutting (38mm*58mm) to obtain a positive electrode pole piece.
  • NMP methyl pyrrolidone
  • PE polyethylene
  • the positive pole piece, the separator film and the negative pole piece are stacked in sequence, so that the separator is in the middle of the positive pole piece and the negative pole piece.
  • the total number of layers of the positive pole piece and the negative pole piece is 31 layers.
  • Examples 2 to 10 and Comparative Examples 1 to 3 have the same preparation method as Example 1, except that the charging process is different;
  • Comparative Documents 4 to 5 are ordinary lithium-ion batteries, and the difference from Example 1 is only the negative pole piece and electrolyte preparation.
  • the current collector was made of copper foil with a thickness of 10 ⁇ m.
  • the negative electrode active material adopts graphite
  • the conductive agent adopts acetylene black
  • the binder adopts styrene-butadiene rubber and sodium carboxymethyl cellulose.
  • the charging process of Example 1 is as follows: the laminated battery is turned into a circle at a charging and discharging rate of 0.1C at 60 degrees Celsius, and then a charging and discharging cycle is performed at normal temperature; the charging process is divided into a constant current (CC) stage and a constant voltage (CV) stage. Stage: CC stage, with 0.08C as the starting current, divided into five steps, each step is charged with constant current for 0.5 hours, the current size is 0.08C, 0.24C, 0.40C, 0.56C, 0.72C; CC stage is 4.40 V is the cut-off voltage. When the voltage reaches the cut-off voltage, the electrode assembly enters the CV stage, and the cut-off current is 0.05C. The rate of constant current discharge is 1C, and the cut-off voltage is 2.80V.
  • Table 1 The differences in the parameters of the charging process of Examples 1 to 10 and Comparative Examples 1 to 5 are shown in Table 1.
  • the test temperature is 25°C
  • the capacity obtained from the first charge is used as the initial capacity
  • the ratio of the capacity of each cycle to the initial capacity is used to obtain the capacity decay curve.
  • the cycle performance of the electrode assembly at room temperature was recorded as the number of cycles from 25°C until the capacity retention rate was 80%.
  • Table 1 shows various parameters and evaluation results of Examples and Comparative Examples.
  • Comparative Example 1 is a conventional CC-CV test, and the cycle number of 80% capacity retention is only 50 cycles, and the cycle performance is poor. This is due to the large current at the initial stage of charging, more lithium dendrites, more side reactions, faster electrolyte, and faster cycle performance decay.
  • Comparative Example 2 a large current was used at the beginning of the cycle. Compared with Comparative Example 1, the generation of lithium dendrites and side reactions were worsened, and the cycle performance dropped sharply.
  • Comparative Example 3 the CV method is directly used for charging, and the current decreases from large to small. Compared with Comparative Example 1, the generation of lithium dendrites and side reactions are more deteriorated, and the number of cycles with 80% capacity retention is only 20 cycles. , the cycle performance drops sharply.
  • Comparative Example 6 when the charging current is below 20% SOC, the charging current continuously increases and then decreases, and the number of cycles for 80% capacity retention is only 30 cycles, and the cycle performance is poor, which is due to the fact that when the SOC is below 20% When the charging current is too large, it is easy to cause the growth of lithium dendrites and the occurrence of side reactions. If the current is too small when the SOC is below 20%, and then the current is reduced, the rate charging performance will be damaged, and the purpose of fast charging cannot be satisfied.
  • Example 8 the current increasing mode is changed, that is, the dwell time of each step is different, and the cycle performance is still improved compared with that of Comparative Example 1.
  • Example 9 the cycle performance of the electrochemical device was further improved by increasing the charging time for each step.
  • Example 10 by reducing the charging time of each step, the number of cycles is reduced, but compared with the conventional CC-CV charging method of Comparative Example 1, it is still improved.

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Abstract

本申请提供了电子装置、用于电化学装置的充电方法、终端和存储介质。电子装置包括电化学装置，电化学装置满足如下特征：在充电过程的第一阶段中，电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，其中，在电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流为A，在电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流为B，A＜B。本申请的电子装置能够实现在与目前的快充所需的充电时间相近的情况下，提高相应的电化学装置的循环寿命。

Description

电子装置、用于电化学装置的充电方法、终端和存储介质 技术领域
本申请涉及电子技术领域，尤其涉及电子装置、用于电化学装置的充电方法、终端和存储介质。
背景技术
锂金属是所有金属元素中相对原子质量最小(6.94)、标准电极电位(-3.045V)最低的金属，其理论克容量可达到3860mAh/g。因此，使用锂金属作为电化学装置的负极，配合一些高能量密度的正极材料，可以大大提高电化学装置的能量密度以及电化学装置的工作电压。锂金属电池在充电过程中，锂会在负极表面沉积。由于锂金属本身具有很高的化学反应活性，沉积过程中会与电解液发生反应，形成固体电解质界面膜(SEI)。随着锂金属的继续沉积，负极发生体积膨胀，原有的SEI会发生破裂，造成局部电场不均匀，导致锂金属优先在这些位置沉积，进而形成锂枝晶。一方面，锂枝晶的形成会持续消耗电解液，导致锂金属电池电解液不足；另一方面，在脱锂过程中，锂枝晶很容易与主体的锂金属失去电接触，导致活性锂的损失，并提高锂金属电池的阻抗。这会严重影响锂金属电池的循环性能，使锂金属电池发生严重的循环衰减。
发明内容
本申请通过优化充电流程来改善电化学装置(例如，锂金属电池)的大倍率充电性能，能够在相近的充电时间下，提高电化学装置的循环寿命。
本申请的实施例提供了一种电子装置，其包括电化学装置，所述电化学装置满足如下特征：在充电过程的第一阶段中，所述电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，其中，在所述电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流为A，在所述电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流为B，A＜B。
在上述电子装置中，其中，在所述充电过程中，所述电化学装置的负极含有锂金属或锂金属的合金。
在上述电子装置中，其中，除了锂之外，所述锂金属的合金还包括金属M，M包括Na、Al、Mg、Si、K、Ga、Fe、Zn、Ag、Y、Sb、In、Sn或B中的至少一种。
在上述电子装置中，其中，所述充电过程还包括在所述电化学装置的荷电状态(SOC)为Y～100％之间的第二阶段，其中X≤Y≤100％，所述第二阶段采用恒压充电方式。
在上述电子装置中，其中，在所述第一阶段中，充电电流呈阶梯递增的方式，阶梯数n≥2，并且每个阶梯的充电时间相同或不同。
在上述电子装置中，其中，所述阶梯递增的方式包括每个阶梯的充电时间相同或每个阶梯的充电容量相同。
在上述电子装置中，其中，在所述第一阶段中，充电电流呈连续递增的方式，或者为先连续递增后保持恒定的周期性方式。
本申请的实施例还提供了一种用于电化学装置的充电方法，其包括：在充电过程的第一阶段中，所述电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，将所述电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流设置为A，将所述电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流设置为B，A＜B。
本申请的实施例还提供了一种终端，包括：至少一个存储器和至少一个处理器；其中，所述至少一个存储器用于存储程序代码，所述至少一个处理器用于调用所述至少一个存储器所存储的程序代码执行上述充电方法。
本申请的实施例还提供了一种存储介质，所述存储介质用于存储程序代码，所述程序代码用于执行上述充电方法。
本申请通过控制充电过程中的充电电流，调控锂的生长行为，能够实现仅需较短的充电时间(例如，快充)的情况下，改善电化学装置的循环性能。即，本申请的电子装置能够实现在与目前的快充所需的充电时间相近的情况下，提高相应的电化学装置的循环寿命。
附图说明
图1示出了本申请的一实施例的电子装置的示意图。
图2至图6示出了现本申请的实施例的随着时间的电流倍率变化的示意图。
图7示出了本申请的实施例的充电方法的示意流程图。
具体实施方式
下面的实施例可以使本领域技术人员更全面地理解本申请，但不以任何方式限制本申请。
目前，锂金属电池还面临着丞待解决的以下问题：1)锂金属本身活泼性极高，尤其是新生成的锂金属，非常容易与现有的有机小分子电解液体系发生一系列副反应，导致锂金属与电解液同时被消耗，循环库伦效率一般小于99.5％，在传统的液态电解液体系中循环库伦效率一般小于90％，大大低于一般的石墨负极体系(大于99.9％)；2)锂金属电池在充电过程中，锂会在负极表面沉积。由于电流密度以及电解液中锂离子浓度的不均匀性，沉积过程中会出现某些位点沉积速度过快的现象，进而形成尖锐的枝晶结构；锂枝晶的存在会导致沉积密度的大大降低，使得能量密度降低，严重时，可能会刺穿隔离膜形成短路，引发安全问题；3)随着锂金属负极的充电-放电，负极极片的厚度会发生剧烈的膨胀-收缩，膨胀与收缩的厚度与负极单位面积活性物质的量及活性物质的比容量相关，也与锂沉积的密度、副反应产物的体积有关；按照目前商用锂离子电池的一般设计，单面锂金属负极满充相对于满放的厚度变化会达到8μm～100μm；这会导致负极极片与柔韧性较差的无机保护涂层之间的界面发生剥离，失去保护效果；4)充电倍率较低，大充电倍率的情况下，锂金属沉积更加容易出现不均匀的现象，加剧锂枝晶的生长，锂金属颗粒大小也会变小，增大与电解液的副反应面积，导致电解液和锂金属消耗加快，循环衰减加快，甚至急剧下降。
目前，为了减少锂金属与电解液的副反应，抑制锂枝晶的生长，解决膨胀-收缩过程中导致的界面剥离和保护层破碎，主要采用以下方法：1)提前保护的方法，即在电化学装置组装之前，在锂金属负极表面通过物理方法或化学方法沉积一层或多层稳定的保护层结构，这种保护层对锂稳定，可传导锂离子，并隔绝电解液与锂金属的直接接触，从而减少副反应；如果保护层 具有较高的机械强度，还可以抑制锂枝晶的生长；然而，由于负极在充放电过程中存在急剧的体积变化，这些覆盖在负极表面的硬度较高的材料很容易发生破裂，导致效用持续降低；2)原位生成保护层的方法，即在电解液中加入一些特殊的添加剂，使之可以与锂金属发生化学反应从而形成更加稳定的SEI膜，阻止副反应的进一步发生；然而一般情况下，添加剂会在充放电过程中不断被损耗，当添加剂损耗完毕后，其保护作用就会消失；3)负极骨架，利用3D集流体、多孔负极骨架等方式，可以为锂沉积提供足够的空间，减少负极在充放电过程中的体积变化；然而，此方法仍然没有对SEI的形成、破坏与再生进行明显的改善，限制了电化学装置的库伦效率与循环性能。
应该理解，本申请的电化学装置包括但不限于通常的锂金属电池，即，负极由锂金属或锂金属的合金形成的电池，而且还包括在充电过程中由于在负极表面析锂而使得负极包含锂金属或锂金属的合金的锂离子电池(充电过程中变为锂金属电池)。例如，负极是传统的石墨、硅基材料等的材料，但是CB远远小于1，当刚开始充电的时候，负极表面并没有锂金属产生，但随着负极满嵌锂至例如LiC 6，C等无法容纳锂离子，则负极表面开始析锂，变成锂金属电池。其中，CB＝(M’*N’*O’)/(M*N*O)≤1.4，其中，M表示正极活性物质占正极活性物质层的质量比例，N表示正极活性物质的克容量，单位为mAh/g，O表示正极活性物质层的单位面积的质量，单位为mg/cm 2，M’表示负极活性物质占负极活性物质层的质量比例，N’表示负极活性物质的克容量，单位为mAh/g，O’表示负极活性物质层的单位面积的质量，单位为mg/cm 2。
如图1所示，本申请的实施例提供了一种电子装置1，该电子装置包括电化学装置2。本申请的实施例的电子装置1没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。在一些实施例中， 本申请的电化学装置包括但不限于锂金属电池或在充电过程中变为锂金属电池的锂离子电池。
在一些实施例中，本申请的电化学装置2满足以下特征：在充电过程的第一阶段中，电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，其中，在电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流为A，在电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流为B，A＜B。即，在电化学装置的荷电状态(SOC)小于等于X(70％≤X＜100％)的第一阶段，使后期(40％≤SOC≤X)的充电电流大于前期(SOC≤40％)的充电电流，可以在满足大倍率充电的相近的充电时间的情况下，提高电化学装置的循环寿命。
这与图2所示的通常的锂离子电池的充电方式是完全不同的。在本申请的充电方式中，随着充电的进行，SOC增大，在充电过程的第一阶段，后期的充电电流大于前期的充电电流。这是由于在低SOC下，锂金属需要克服更多的能量进行成核，因此大倍率下容易带来更大的极化，从而导致局部电场不均匀性增加，锂枝晶生长加剧，副反应增多，最终导致电化学装置的循环寿命极大缩短。而在高SOC的情况下，在有足够的成核位点的情况下，电化学装置可以支持更大的充电倍率。因此，通过使后期的充电电流增大的方式，可以在相近的充电时间下，提高电化学装置的循环寿命。
在一些实施例中，在充电过程中，电化学装置的负极含有锂金属或锂金属的合金。在一些实施例中，电化学装置的负极可以本身就是锂金属或锂金属的合金，即，电化学装置的负极是由锂金属或锂金属的合金形成的。在一些实施例中，电化学装置的负极可以是常规的石墨等，但是随着充电过程的进行，在负极析出锂金属，使得负极的表面为锂金属或锂金属的合金，变成锂金属电池。因为对于负极含有锂金属或锂金属的合金的电化学装置，如果采用常规的充电方法，即恒流大电流，会使电解液和锂金属消耗过快，并且产生锂枝晶，降低电化学装置的循环寿命。
在一些实施例中，在上述锂金属的合金中，除了锂之外，还可以包括金属M，M包括Na、Al、Mg、Si、K、Ga、Fe、Zn、Ag、Y、Sb、In、Sn或B中的至少一种。通过采用锂金属的合金，能够降低锂金属的活性，减少副反应的发生。
在一些实施例中，充电过程还包括在电化学装置的荷电状态(SOC)为Y～100％之间的第二阶段，其中X≤Y≤100％，第二阶段采用恒压充电方式。由于电化学装置快充满电的时候，电阻较大，从安全性和防止过充的角度，可以采用恒压充电方式。
在一些实施例中，在第一阶段中，充电电流呈阶梯递增的方式，阶梯数n≥2，并且每个阶梯的充电时间相同或不同。图3和图4分别示出了实施例1和实施例8的随时间的电流变化的示意充电方式。通过采用逐步增大充电电流的方式，可以在相近的充电时间下，提高电化学装置的循环寿命。这是由于在低SOC下，锂金属需要克服更多的能量进行成核，因此大倍率下容易带来更大的极化，从而导致局部电场不均匀性增加，锂枝晶生长加剧，副反应增多，最终导致电化学装置的循环寿命极大缩短，所以在低SOC下采用较小的充电电流以避免上述问题。而在高SOC的情况下，在有足够的成核位点的情况下，电化学装置可以支持更大的充电倍率，从而在减少充电时间的同时提高电化学装置的循环寿命。
在一些实施例中，阶梯递增的方式包括每个阶梯的充电时间相同或每个阶梯的充电容量相同。通过采用这种递增方式，便于充电过程的控制以及电化学装置的充电管理。
在一些实施例中，在充电过程的第一阶段中，充电电流呈连续递增的方式，或者为先连续递增后保持恒定的周期性方式。图5和图6分别示出了这两种方式。
如图1所示，本申请的实施例还提供了一种用于电化学装置的充电方法，其包括步骤S101：在充电过程的第一阶段中，电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，将电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流设置为A，将电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流设置为B，A＜B。在一些实施例中，在充电过程中，电化学装置的负极含有锂金属或锂金属的合金。
在本申请的充电方式中，随着充电的进行，SOC增大，在充电过程的第一阶段，后期的充电电流大于前期的充电电流，这样可以避免前期电流过大引起的锂枝晶生长以及副反应增多的问题，改善了电化学装置的循环性能，另外，由于第一阶段的后期的电流较大，也满足了大倍率充电的要求，节省 了充电时间。因此，通过使后期的充电电流增大的方式，可以在相近的充电时间下，提高电化学装置的循环寿命。本申请的充电方式特别适合于诸如锂金属电池的电化学装置。
此外，本公开还提供一种终端，包括：至少一个存储器和至少一个处理器；其中，所述存储器用于存储程序代码，所述处理器用于调用所述存储器所存储的程序代码以执行上述充电方法。应该理解，本公开实施例中的终端可以包括但不限于笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
此外，本公开还提供一种计算机存储介质，该计算机存储介质存储有程序代码，程序代码用于执行上述充电方法。本申请的计算机存储介质可以是计算机可读信号介质或者计算机可读存储介质或者是上述两者的任意组合。计算机可读存储介质例如可以是——但不限于——电、磁、光、电磁、红外线、或半导体的系统、装置或器件，或者任意以上的组合。计算机可读存储介质的更具体的例子可以包括但不限于：具有一个或多个导线的电连接、便携式计算机磁盘、硬盘、随机访问存储器(RAM)、只读存储器(ROM)、可擦式可编程只读存储器(EPROM或闪存)、光纤、便携式紧凑磁盘只读存储器(CD-ROM)、光存储器件、磁存储器件、或者上述的任意合适的组合。
应该理解，本申请的锂金属电池或充电过程中转变为锂金属电池的锂离子电池的制备方法不作限定，可以采用已知的方法制备。例如，将正极极片、隔离膜、负极极片按顺序卷绕或堆叠成电极件，之后装入例如铝塑膜中进行封装，注入电解液，化成、封装，即制成锂离子电池或锂金属电池，其中锂金属电池的负极通常为锂金属或锂金属的合金。
下面列举了一些具体实施例和对比例以更好地对本申请进行说明。
实施例1
负极极片的制备：负极集流体为12μm的铜箔，两面覆盖着厚度为50μm的锂箔，将负极极片裁切成(40mm*60mm)的规格待用。
正极极片的制备：将正极活性物质LiNi 0.5Co 0.2Mn 0.3O 2、导电剂导电炭黑、粘结剂聚偏二氟乙烯(PVDF)按重量比97.5：1.0：1.5的比例溶于N-甲基吡咯烷酮(NMP)溶液中，调配成固含量为0.75的正极浆料，搅拌均匀。采用铝箔作为正极集流体，将正极浆料涂覆于正极集流体上，经过90℃条件下干燥、冷压、裁切(38mm*58mm)后得到正极极片。
电解液的制备：在干燥氩气气氛中，首先将二氧环戊烷(DOL)、二甲醚(DME)以1:1的体积比混合，得到有机溶剂，然后在有机溶剂中加入锂盐双三氟甲基磺酸亚酰胺锂(LiTFSI)溶解并混合均匀，得到锂盐的浓度为1M的电解液。
锂金属电池的制备：选用厚度为15μm的聚乙烯(PE)作为隔离膜，将正极极片、隔离膜、负极极片按顺序依次叠好，使隔离膜处于正极极片和负极极片中间起到隔离的作用，正极极片和负极极片的总层数为31层，叠好后，用胶带将整个叠片结构的四个角固定好，置入铝塑膜中，经顶侧封、注液、封装后，最终得到锂金属叠片电池。电池通过夹具均匀施加0.5MPa的压力，用于后续的测试。
实施例2～10和对比例1～3与实施例1的制备方法相同，仅是充电过程不一样；对比文件4～5为通常的锂离子电池，与实施例1的差别仅在于负极极片和电解液的制备。对比例4～5的负极极片的制备：集流体采用铜箔，厚度为10μm。负极活性物质采用石墨，导电剂采用乙炔黑，粘结剂采用丁苯橡胶和羧甲基纤维素钠。将负极活性物质、乙炔黑、丁苯橡胶和羧甲基纤维素钠按质量百分含量比96：1：1.5：1.5混合后分散于去离子水中形成浆料，搅拌均匀后涂布于铜箔上，干燥，形成负极活性物质层，负极活性物质层的厚度为45μm，冷压、分条后得到负极极片；对比例4～5的电解液的制备：在含水量小于10ppm的环境下，将六氟磷酸锂与非水有机溶剂(碳酸乙烯酯(EC)：碳酸二乙酯(DEC)：碳酸亚丙酯(PC)：丙酸丙酯(PP)：碳酸亚乙烯酯(VC)＝20：30：20：28：2，质量百分含量比)按质量百分含量比8：92配制以形成锂盐浓度为1mol/L的电解液。
实施例1的充电过程如下：叠片电池在60摄氏度以0.1C的充电和放电倍率化成一圈，然后在常温下进行充放电循环；充电过程分成恒流(CC)阶段和恒压(CV)阶段：CC阶段，以0.08C为起始电流，分成五个阶梯，每个阶梯恒流充电0.5小时，电流大小分别为0.08C、0.24C、0.40C、0.56C、0.72C；CC阶段以4.40V为截止电压，当电压达到截止电压时，电极组件进入CV阶段，截止电流为0.05C。恒流放电的倍率为1C，截止电压为2.80V。实施例1～10和对比例1～5的充电过程的参数的差别示于表1中。
下面描述本申请的循环性能的测试方法：
测试温度为25℃，以首次充电得到的容量为初始容量，以每一循环的容量与初始容量做比值，得到容量衰减曲线。以25℃循环截至到容量保持率为80％的圈数记为电极组件的室温循环性能。
表1示出了实施例和对比例的各个参数和评估结果。
表1
Figure PCTCN2020106782-appb-000001
Figure PCTCN2020106782-appb-000002
对比例1为常规CC-CV测试，80％容量保持的循环圈数仅为50圈，循环性能较差。这是由于充电初期电流较大，产生锂枝晶较多，副反应增多，电解液加快，循环性能衰减较快。
通过比较实施例1～5和对比例2可知，同样的充电时间，对比例2的初期充电电流较大，循环性能较差，80％容量保持的循环圈数仅为25圈，而实施例1～5基本在100圈左右。因此，通过采用本申请的充电方式，能够在充电时间相近的情况下，大幅改善电化学装置的循环性能。
对比例2的循环初期采用很大的电流，相对于对比例1，锂枝晶产生和副反应生成情况更加恶化，循环性能急剧下降。
在对比例3中，直接采用CV方式进行充电，电流从大到小递减，相对于对比例1，锂枝晶产生和副反应生成情况更加恶化，80％容量保持的循环圈数仅为20圈，循环性能急剧下降。
在对比例4中，针对锂离子电池，充电电流不断增大时，会出现析锂。而在对比例5中，在锂离子电池的充电电流不断减小时，此时不会出现析锂。
在对比例6中，充电电流在20％SOC以下时充电电流不断增加，之后减小，80％容量保持的循环圈数仅为30圈，循环性能较差，这是由于在SOC处于20％以下时充电电流过大容易导致锂枝晶的生长和副反应的发生。如果在SOC处于20％以下时电流太小，之后又减小电流，则会损害倍率充电性能，不能满足快充的目的。
通过比较实施例1～5可知，随着初始电流不断增大，截止电流部件减小，循环圈数出现先增加后减小的趋势。循环圈数先增加是由于截止电流的降低，因为后期的大电流对电化学装置的循环性能有一定的恶化作用，因此，随着截止电流的不断减小，循环性能随之改善。然而，随着初始电流进一步增大，此时初期锂枝晶的生长对负面效应逐渐起主导作用，从而导致循环性能又开始恶化。
通过比较实施例6～7可知，在阶梯数大于5时，随着阶梯数的提升，电化学装置的循环性能稍有提升，但是并不是很明显。
在实施例8中，电流增长方式改变，即每个阶梯停留的时间不同，循环性能相对于对比例1仍然有改善。
在实施例9中，通过增加每个阶梯的充电时间，电化学装置的循环性能进一步提升。
在实施例10中，通过减少每个阶梯的充电时间，循环圈数有所降低，但相对于对比例1的常规CC-CV充电方式仍然有所提升。
以上描述仅为本申请的较佳实施例以及对所运用技术原理的说明。本领域技术人员应当理解，本申请中所涉及的公开范围，并不限于上述技术特征的特定组合而成的技术方案，同时也应涵盖由上述技术特征或其等同特征进行任意组合而形成的其它技术方案。例如上述特征与本申请中公开的具有类似功能的技术特征进行互相替换而形成的技术方案。

Claims (10)

  1. 一种电子装置，其包括电化学装置，所述电化学装置满足如下特征：
    在充电过程的第一阶段中，所述电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，其中，在所述电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流为A，在所述电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流为B，A＜B。
  2. 根据权利要求1所述的电子装置，其中，在所述充电过程中，所述电化学装置的负极含有锂金属或锂合金。
  3. 根据权利要求2所述的电子装置，其中，所述锂合金还包括元素M，M包括Na、Al、Mg、Si、K、Ga、Fe、Zn、Ag、Y、Sb、In、Sn或B中的至少一种。
  4. 根据权利要求1所述的电子装置，其中，所述充电过程还包括在所述电化学装置的荷电状态(SOC)为Y～100％之间的第二阶段，其中X≤Y≤100％，所述第二阶段采用恒压充电方式。
  5. 根据权利要求1所述的电子装置，其中，在所述第一阶段中，充电电流呈阶梯递增的方式，阶梯数n≥2，并且每个阶梯的充电时间相同或不同。
  6. 根据权利要求5所述的电子装置，其中，所述阶梯递增的方式包括每个阶梯的充电时间相同或每个阶梯的充电容量相同。
  7. 根据权利要求1所述的电子装置，其中，在所述第一阶段中，充电电流呈连续递增的方式，或者为先连续递增后保持恒定的周期性方式。
  8. 一种用于电化学装置的充电方法，其包括：
    在充电过程的第一阶段中，所述电化学装置的荷电状态(SOC)小于等于X，70％≤X＜100％，将所述电化学装置的荷电状态(SOC)小于等于40％时的平均充电电流设置为A，将所述电化学装置的荷电状态(SOC)为40％～X之间的平均充电电流设置为B，A＜B。
  9. 一种终端，包括：
    至少一个存储器和至少一个处理器；
    其中，所述至少一个存储器用于存储程序代码，所述至少一个处理器用于调用所述至少一个存储器所存储的程序代码执行权利要求8所述的充电方法。
  10. 一种存储介质，所述存储介质用于存储程序代码，所述程序代码用于执行权利要求9所述的充电方法。
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CN114497781A (zh) 2022-05-13
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